Ben1098

You have more tests to perform: 1. Raise all 4 wheels......jackstands. 2. Remove the servo gear motor assy from the front diff. Leave connectors on. KEY ON Have assistant cycle the buttons on the dash. The pinion gear should should have 3 distinct stops....2WD, "3WD", 4WD. If this works ok....check the diff rack function. 3. The servo motor pinion gear (the 3 stops) drives the rack back and forth for 3 stops. You are going supply the Left to Right to Left motion to the rack "block". Have assistant rotate wheels as you slide the rack thru the 3 positions to get the 2, 3, 4WD diff functions. If diff functions correctly, slide the rack to center position (usually the correctly timed position is off center by 1 to 2 teeth). Then, select 3WD on the buttons (center).......insert slowly to engage the pinon to the rack. Test button/wheel rotation combinations. Adjust rack position to fine tune if required. NEVER SHIFT INTO 4WD UNDER POWER/LOAD. That will break the little rack pin or shift fork. ALSO.....NO 4WD ON PAVED SURFACE WITH TURNING. BINDS UP THE DRIVE TRAIN. CHOW

Go to Engine Coolant Sensor on top of the head.....will look like a mini spark plug. Single wire. This runs to ECM. The sensor is a special resistor that changes resistance value.....most are NEG....meaning the value goes down as the probe end in the coolant gets hotter....and of course the reverse also for R high at low temp. Test time DVM DC VOLTS. Pull and probe the ECT plug....KEY ON. You should have +5 ish Vdc....source is ECM signal input that has an INTERNAL resister in series to +5 source. The DVM "sips" current....thus NOT A LOAD. Next....DVM R range. N to head body and P to sensor tip connection. You should have some resistance (don't have specs) say cold 10K to 100K. An open sensor pellet will be INFINITE...same as leads apart.....which is bad. Your message stated the Error Code was high voltage or open circuit. With out a load....Meter doesn't count.....you get +5Vdc from ECM at ECT sensor connecter. If ECT is good (a resistance load) AND wiring is good, the voltage will be less than +5 due to voltage divider action. The changing sensor will change the inputs voltage....calibrated to temp to control fuel delivery.....Like the TPS, a swing from 1V to 4V. That's how it is supposed to work. Your problem is one of 3 items harness/connectors/ECT. If no +5 at connector, check at ECM....if good, find the open ckt. The open circuit makes the ECM think it is at the South Pole @ - 40 deg C....dumps extra fuel for a COLD start. Check spark plug for sooty black or wet electrode....clean and dry or start with a fresh plug because fouled plugs may look sorta ok, but no or weak spark. CHOW

Try a simple test....the finger compression test. Remove spark plug. Put it back into cable and lay on clean as on no mud frame gnd....away from engine head. Push finger/thumb over spark plug hole tightly. Have helper crank over engine. Good compression will blow your finger off with a nice POP! Another clue.....everything is installed and crank over engine. You should hear the motor cranking sound change....sorta like a Whop Whop Whop Whop. This is the cranking speed dropping during the compression stroke starter loading then spinning faster during the other 3 phases of 4 stroke engines. Chow

A fast test is just use 2 jumper/clip leads. The signal will be good enough if NOT routed against harness. If miss fire or sputtering, shield the signal wire. Grab some Al foil strip 1/2" wide...wrap length wise....finger roll tight...masking tape here and there and the ends (stay off the ends...no shorts) AND take a 3rd clip lead....attach to foil and a good ground (signal gnd). Shielded cable on the cheap.

Tried again....no answer....try [email protected] Guessing what your question would be: 450 ohm vs 210 ohm coils. Seen both used. The 450 ohm had failure problems..thermal good/bad self healing. Tech info...the output is the real object. Internal construction better magnet and heavier wire/less turns (lower resistance) but gives equal pulse output. Chino service manual...copy of Yamaha Rhino SxS clone copied Yam specs and NOT what was in machine. Pickup coil. Output is signal and signal gnd taken off BOTH ends of the coil windings. Tech.....the pulses due to make/break of magnetic circuit are + and then - repeating as the flywheel rotates. Coil can be wired wrong.....as in backwards....resulting in a timing error. Most ign modules trigger off + edge. Thus timing will be off. Shielded wire consists of insulated signal wire(s) wrapped with a foil shield and then a bare (drain) wire wrapped around foil...all with a outer insulation jacket. You application has a single center wire (signal) and the bare drain wire is signal gnd. Smash the cable and the foil/bare wire will short to the inner signal conductor. I've seen a wire tie too tight break down the insulation on well used machines. In your case 1. Pickup R was "correct" at output at engine. 2. Measured at Delphi ECM very low R...SHORT.....due to insulation failure in S cable. 3. Measured R in both center and drain wires and OK.....these wires are still intact....will both be low R. 4. The internal short will kill the weak pickup signal...ECM no timing signal....dead.

Did you send a LA area code phone number. I called 2x from 812 xxx xxxx..no answer nor voice mail...this you

The pickup coil signal wire is shielded due to ECU input can "see" other "trash" like the starter current pulses. You have a smashed cable which shorts signal to GND....this the mohm reading you get. Shielded cable is toast....cut back the cable to leave two (2) pigtails. Connect the open ends....ECM input and the pickup coil output(s). Go to electronics store a buy a chunk of shielded cable...take sample along.....SOLD ER all 4 joints...route new wire run far away from starter HOT and the 3 PH stator to Regulator wires

Do a simple voltage test on the DELPHI ECM.....BLK connector.....as follows: Pin 18......+12 Vdc....Always Hot...Battery Pin 15......+12 Vdc......ONLY with ign key ON. 0 Vdc with key OFF. Also power grounds on BLK Pin 2 and GREY Pin 9.

CVT belt and pulleys have water and clay slop inside. Open up and clean/dry pulleys. May need new belt depending on what the slop was. Blow out all the stuff from Drive and Driven pulleys moving parts.

ECM most likely not getting 12v on BLACK connector at 2 places. Always Hot on p. 18 and also p.15 with KEY ON. Either missing ECM is non working.

Sounds like slop for fuel. pull the fuel pump connector at fuel tank top.......this keeps the slop from loading up the cylinder. Pull spark plug and use a propane or MAPP torch to dry out the insulator tip. Reconnect to the spark plug cable and lay it on the frame away from engine. Have remote starter or helper crank over engine while you give it the finger over spark plug hole compression test....should blow off finger with a POP. Engine oil is cold....cylinder/rings might be dry....wet them by fogging the cylinder with WD40.....more compression???? If not, run the valves and be careful NOT to stop in the cams compression release area....i.e. go past TDC a bit (25 deg) then roll back to TDC. Reload the spark plug.....remove air filter lid....start cranking and then give it a shot of the go juice (starter fluid)..should light off and then die....repeat several times to warm the engine some. Reconnect the fuel pump connector......give a short shot of go juice and crank over. Slop will run poorly or not at all. If you have slop, drain the fuel tank with a hand squeeze pump. The fuel pump "holds" some fuel in the cup. You have to bleed/rid the system of the slop. Remove hose from injector (warm hose to make soft and pliable so no damage and crumbs break loose. USE gasoline (no OH/water mix) and fill tank. KEY ON-OFF cycle to pump/fill the line with fresh gasoline....run into a clear jar and see if there is some phase separation------gas on top and yellow soup on the bottom. The injector will have slop yet so use the starter fluid to enable the engine to run and push thru the slop....IF all good, the motor will now run only on the FI system. The cold temp input to ECU will squirt more fuel (mimic a choke on carb) so a batch of slop can wet down the spark plug and cause it to blow out under compression.

I bought an almost NEW swimmer....drunk fishing buds went to river....to not get a DWI....left MASSY at river....best part....left keys in the ignition....river sandbar recovery. Hoped for best with this pig in a poke. Sanded piston/cyl. Crank bearings "rough". Even the transmission bearings had multiple bind spots. New oil pump. Still money ahead. The rear output shaft was leaking BEFORE the swim by the oil slick on present.....BTW, watch this very close....sealant gets hard and leaks not at the seal BUT thru the spline...NICE. That was 4 years ago....keep the oil level up and CLEAN and watch for air lock in coolant. Special bleed procedure...FRONT RAISED about a foot...makes radiator higher than engine head bleed screw. The Al tubes that run in the bottom floor pan HAVE TO HEAT UP WHEN WARMING UP MOTOR....this means the coolant is flowing to the radiator. BTW, it is a YAMAHA RHINO clone with motor parts interchangeable......I suspect the cam with it's compression release was made by the same SUB......I worked on BOTH units that the weld assy step was WRONG EXACTLY IDENTICAL.....so my spare cam (modified/fixed) went into a RHINO. My experience......they all have problems (repeat problems)...worst is hillside + idle oil failure (crispy head). Back to RHINO/HISUN (these motors are in everything....big box). Common failure in R, Hisun fixed with a more robust bearing so these parts are not interchangeable. Electrical problems...don't go there. Ho would not start while cranking....will catch when starter is released. Even a "solid" design will fail when the starter hot cable is bundled with the pickup coil signal wires.....same as a RAM with the alt cable trashing the ECM inputs. Gotta go.

The seat rear has 3 molded plastic "fingers" that go under the 8mm rod bent/formed to make a "receiver" to hold the rear of the seat. Past problems were the rod was deformed (motor drop in????)....just straighten back out to gain the req'd clearance. Once the bent rod receiver was "off location" rubbed on the side instead of the top. This fix uses a flap wheel to GENTLY trim the offending plastic finger. If still not finding the problem, measure the 3 finger L-R locations....compare to the welded receiver rod openings. Further, measure the top-bottom thickness and make a stack of pop sickle sticks (or whittle from a lathe) us use as a plug gauge. As far as the FRONT latch pin not working......look into the front pin hole. See the 4 mm spring sitting crossways that moves with the seat latch lever. Released, the 4mm spring (the section you can see) will extend about 8mm or so into the molded hole.....latch pulled, the 4mm spring is retracted past the hole diameter. This 4mm spring is what snags on the pin (sticking up from the body) with the annular machined 5mm groove. Past problems here.........plastic latch lever spring grabbing projection GONE as in broken off. NO spring movement or not full travel. Next, the seat will go on BUT not latch...even with a little bap on the seat front. Problem is the latch assy cannot drop deep enough on the pin to get captured by the 5mm annular groove. SHIM the latch to make it "lower" i.e. remove screws, make a plastic shim (liquid laundry soap jug) with screw holes and try again. Last, pin was hit (engine drop in???) and have an obvious banana look......extra...dry or binding 4mm spring is "smashed between the seat latch halves. Careful round file trimming req'd here. CHOW

Find the Delphi ECM. Should have 2 connectors----gray and black. There are two +12vdc inputs. One (pin 18) is ALWAYS HOT (like memory on radio) and then the other(pin 15) is hot only with KEY ON. Don't have ECM pin out handy so I can't state which color connector. With KEY OFF, remove both connectors (identical except color) and find the fine print molded pin numbers. KEY ON. Needle probe (don't stab and ruin the terminal) the pin(s) number looking for the 2 +12v inputs. After finding, KEY OFF to see if pin 15 goes away (check to see if you are in the right track). Problems found in past....fuse blown, smashed connector, mouse house chews, and loose connector. There is not a good wiring diagram. The same DELPHI ECM module (retuned) is on late B & S FI V-Twin lawn mower engines and the pinout can be found with YAHOO search using DELPHI ECM PINOUT. Without the two supply pins, the ECM plays dead....check before spending $$$$$$$$$$$$$$$$$. CHOW

Travis.....just read starter tale of woe. The 2nd starter (CHINO) had an internal open circuit i.e. the brushes or armature. Older starters did not have stopper brush holders, and as the brushes wore down (and spring tension less), the Cu braid cable would burn a trench in the commutator Cu bars....no fix except to have the armature rebuilt. Newer starter brush plates have the stopper and then after wearing down to where the brushes Cu braided wire hit the stopper bar, end up having a poor contact connection....new (full length) brushes, clean armature, and good to go. Tapping will "fix" in early stages to get you back home. Another problem is holding the key on and the motor not turning....will generate a hot spot and lift the Cu bar. Another problem is the edges of the Cu bars will burn away leaving a "rounded" not flat bar.....since the brushes cannot hit a 'full' bar width, current is less....fix is to turn down commutator bars on lathe...within reason...for a second chance before the scrap barrel. Explaining your test: You had the same voltage on the battery terminal AND the starter motor hot terminal...case is GND. The battery cable has resistance so expect a small drop say .4 to .6 v drop. The solenoid contacts (big ums) are about 0 v if good. NO CURRENT FLOW. Current flows from HOT terminal in to a brush (2 brush plate) or opposite brushes (4 brush plate)-----thru commutator Cu bars.....thru Cu armature windings----back to the CU bars...then out the single or dual brushes to case--- GND. What to look for from past T/S findings. Brushes worn.....too short or light pressure. Weak springs. Spring hung on brush holder..as in placed not on the slot on the back side of brush. Spring holder "box" not square....like something hit it at assy or stepped on...makes the brush bind. Mechanical........worn small bushing or dry big end bearing making it hang then burn the Cu bar. You might be able to save the chino....but don't expect a rebuild kit to fit. RICK'S was our vendor of choice a few years back. He had stators, regulators, CDI, etc. don't know if he is still in business. Pricing on OEM parts. 80 and 90's 100% markup........COST $60 MSRP $120. Then dollar/yen hit, COST $80 MSRP $120. That was how the pricing line was held......There are tons of OEM parts out there from Dealers inventory auctions/liquidations who went belly up. Some sellers pass on a good deal while others are greedy.

DIFF problem....you will have 2 connectors...one to switch power + to - and - to +......this runs the small electric DC motor that slides the rack (behind/under the black round shift servo) from left to right to left. There are 3 positions.....2 WD, "3 WD" which is an open diff where if front end is lifted, the wheels rotate in opposite directions (with drive shaft locked) and then 4WD which locks BOTH fronts together. Someone in the past has shifted into 4WD UNDER LOAD (and moving)....SNAP CRACKLE POP with emphasis on the POP. DO the rack test (remove the black shift module....bolts here.....and slide the rack L to R to L. Be aware that the position of the rack has to be "timed" to the servo unit. Write down the dash switch(s) position (I like 3 WD) AND where exactly where the rack is sitting (in the middle slightly off center for 3 WD). Test the servo by having another person run the buttons and you look for the gear to turn and motor to buzz. The gear will go CCW and CW and CCW...exactly the way the rack should slide back and forth to select the desired function. If the rack slides with no resistance from side to side...internal busted push pin on rack. If working, the rack will move slightly and then stop because you have to rotate the wheels (spin the diff) to align the diff gears and then finish the "shift" The servo has a "wind-up" spring between the electric motor drive and the gear output that "winds up". What this does is put pressure (like you are doing with your hand) on the rack waiting for the gears to align. There are contact tracks/Cu brushes (limit switches) that rotate with the drive reduction gears to send back 12 v OR open to electrically shut off the motor power so as to not bust up the works....winds spring up waiting for alignment....but not over driving the plastic gears. DECOMPRESSION problem. You have 2 exhaust valves (depending on the year either 2 or 3 intake valves). The exhaust valve on the far side (away from the cam gear AND center located decompression cam/flyweights/springs) has 2 functions. When starting the flyweights are IN (spring tension) and the DC cam is rotated to push up a pin that rubs the rocker pad. The exhaust valve then opens slightly as long as the pin (5mm ish Dia.) is rubbing on the rocker pad. SINCE the valves are adjusted at TDC on compression stroke, there is a chance you might still be sitting on the pin and not know it-----wrong valve adjustment. The fix is to rotate past TDC then come back. You should hear and see the valve do its thing. You will see a deep stroke on both exhaust valves BUT only a slight opening from compression release function. Again there are 3 things found wrong in my past experience. 1. The pin had chipped out a groove in the slipper pad........no longer opened enough--the quick death method--chunks out at one time. 2. The decompression cam (in the center of the valve cam) has wear on the corner edge and gradually gives a shorter pin stroke length AKA, slow death. 3. Factory defective part. Hard to crank out of the crate. Found in BOTH Yam RHINO and HISUN Massimo. THE mistake IS identical----same supplier for both!!!! The fly weights are stamped main body and an extra "weight segment" welded to the main body. Extra weight was not aligned at weld station correctly and resulted the DC cam having reduced rotation....thus a die grinder fix. Q-LINK Youtube video posted on cam replacement. Entertaining on the chain/cam timing with CUT AWAY. HE! HE! HE! Give this post and video to the fella you are going to have a look see. Should give insight on what is happening.

Travis was on the right track. You have a strong running engine after you get it to start. The split vac hose was just a bump in the middle of the search, right? Carb/fuel problems will generate runability problems before and after starting. Bad connections, weak battery, parasitic drain, burned solenoid contacts, worn starter brushes reduce the power delivered and used to crank it over. Travis test of pulling spark plug...you said the motor spins over just fine with the spark plug removed......no load except friction and valve spring loading. You video was the TELL. Compression release is not doing it's thing. Totally random as it depends on where the motor stops (how far from the Compression stroke) AND how long the motor set since last crank/run......oil drain down and piston/rings get "DRY" lowering the compression. Fog cylinder or crank to splash/lube piston/rings....compression climbs back up. Physical example.....you want to push a small car on a level driveway into the garage. Problem is the rain shedding slope or a seam in the pours at the door. Would you push to the incline or bump and then STOP only to then try push it up the incline or over the seam??? NOPE, you would take a RUN at it. Same for the poor starter......no compression release.......grunt city per the video clip. The clip shows the "front" of engine with the intake valve cover (double lid) but not the exhaust. 3 valves? Maybe 4 valves? Should have a 2 into 1 exhaust header and 2 ea of the round screw off caps for adjusting the exhaust at the "rear" of the engine. Compression release works by SLIGHTLY opening for a SHORT time an exhaust valve during the compression stroke. Less grunt....motor gets a RUN at spinning over faster which will build compression more (less time for the slight EX valve to be open and leak off some of the fuel/air mix) to the point it is high enough to light off.... if the fuel/air mix is right. Exhaust valve adjustment is set between the rocker screw adjuster and the valve stem top face. This is important for the RUN function. The START function will be hindered if the valve is set too loose (wider gap) as it cannot open the valve slightly as much or not at all. Too tight will result leakage.....burnt valve seat/face when the whole motor warms up and EXPANDS as in the valve stem gets longer. ADJUST THE VALVES. FOR THE DOWN SIDE..................there are a couple of BAD things to go wrong.....one was a incorrectly machined flyweights (located on the camshaft gear) from factory and the other two are wear of the compression release "CAM" (located inside the valve camshaft) OR the ball/pin had worn a grove in the rocker/follower. ANY of these will result in NOT opening the EXHAUST SLIGHTY for a short DURATION=COMPRESSION RELEASE. ADJ valves and go from there. BE sure to get off the compression release section and only have the slipper pad adj screw to valve stem face....that that can also have wear problems. Lots to check here but that is what it is. The last problems require the rocker cover and cam to be pulled along with IF a pin/ball grove cut into the rocker/follower. The factory mistake can be fixed with a burr and die grinder (gets too deep for here right now of what and why details).

Sorry, I forgot to mention that a shorted Regulator can overheat and burn off the insulation on the stator winding coils....usually takes out every 1/3 pole piece around the clock as it is a 3 Phase system. Do a resistance test on the Y-Y-Y pigtail (regulator disconnected). R = .3 ohm Y to Y (3 times). If all 3 R readings are close, do a load test to mimic what the stator windings have to do in real life. Test with engine running----no load VOLTAGE will be 25-30 VAC at idle and up to 80 or so at 4000 RPM. LOAD TEST involves drawing current (POWER) off the 3 Y-Y stator pigtail leads. I like a 40 W incandescent bulb screwed into a pigtail socket available at electrical/hardware/HD/Lowe's etc. Touch any 2 of the stator output legs combinations (3X) and the bulb will glow at idle...30 VAC on a 120 VAC rated bulb. SLOWLY raise the engine RPM....brighter and brighter....that is good. On a hot 2 Phase system like H-D, you will be buying a new bulb if not careful.

You toasted the regulator.....NO CHARGE......motor running charge test voltage will be sitting at the battery's present terminal voltage......discharged say to 11.7v. The regulator is a shunt type------dumps EXCESS voltage, thus current to GND. The stator and the rectifier/regulator's output is "puny" compared to a light trucks RUNNING (100A area) alternator and 800 CCA battery. NEVER hook up to a smaller system EVEN right after pulling into location to give a jump as the host battery is still at 13.6Vv to 14.2V after shutting down engine. The poor regulator is trying to HOLD it's setpoint regulated output voltage by dumping the excess. POOF! The potting shatters when a F350 Diesel with 2 batteries and 120A alternator (running of course) is the host. Do a regulator diode test checking for F/B voltage on the 6 diodes from Y-Y-Y to R & B i.e. DIODE FUNCTION on digital meter to Y to R, Y to B.....times 3 for each alternator leg input...... .6v and OPEN. This does NOT test the SCR (switches) that do the actual dumping of excess current.....might show up in test as .0000001v instead of .6v. Killing off only 1 diode will result in only 1/3 the possible rated output. SO, you could be charging at idle with lights and engine electronics load BUT the winch motor will take more than the system can recover BETWEEN the adjustments to the snow plow height....slowly discharge to a no start condition.

B & S VANGUARD ignition problem. YES, same old magneto coil design from way back....no need for a battery to supply the coil current...the flywheel magnet rotating thru the mag coil "legs" is the power source. The mag coil has a low turns PRIMARY and a high turns HV output to the spark plug. 60's type lawnmowers used mechanical points (mounted to engine case I.e. GND) located under the flywheel that opened the primary coil circuit as the piston approached TDC-----8 deg BTDC. This same coil lead went to a condenser AND the throttle activated kill switch....before that a lever switch....before that, no electrical connection but a metal tab that was flipped over to short the top of the spark plug. Bottom line: KILL: the coil current is conducted shorted to GND. RUN: With the kill switch OFF.......the points do the same thing when they were closed.......BUT......OPEN (exactly timed by point gap and the ground/machined POINTS CAM flat spot on crank arm) to produce a spark from the mag coil HV output. ALSO, the flywheel magnet has to rotate under the mag coil "legs" or coil pole pieces AT the same exact time to generate a MAXIMUM magnetic field. The maximum magnetic field is what generates the NEG current pulse that flows to the CLOSED points. The desired spark timing is when the piston is at say 8 deg BTDC. The points are supposed to OPEN at this time in rotation for correct ign timing. NOTE: The flywheel key LOCKS the flywheel with the molded/cast magnet poles to the crank for it's share of the timing show. (sheared or 1/2 sheared flywheel KEY will be OFF TIME and therefore NO SPARK). The generated mag coil primary current PEAKS, the points now OPEN, and now the energy stored has to dump somewhere----somewhere being the HV coil windings-----SPARK. Vanguard is a 90 deg. V-twin...think of it as 2 singles scabbed together. Each cylinder has a Mag ignition coil. The magnet in the flywheel rotates under the respective coils with respective pistons at BTDC. IF cylinders were 180 deg. apart, there would be no need for the diode cable harness......a wasted spark system like the '70s era dual point in-line four cyl motorcycles AKA rice burners--H,Y,K, S. The timing is the 8 deg. BTDC with the wanted SPARK on the COMPRESSION stroke and the wasted spark at valve overlap...which does nothing because of the already burnt exhaust gasses are being pushed out. The electronic ignition module has an "electronic switch" that close/open(fire) for BOTH cylinders as they go thru the 8 deg. BTDC desired spark timing. The coils have to be ISOLATED from each other----DIODES......that pass the NEG pulse from CY 1 (thus the polarity requirement of cathode(band) facing the magneto coil primary) to the "POINTS" but NOT to the CYL 2 (which is BLOCKED by it's own diode----wrong polarity of pulse) coil that is not charges as of yet.......Diode failure will circumvent the sudden OPEN CIRCUIT req'd to transfer ALL the energy to the respective HV side of the coil. Results in no spark/wimpy spark/fouled plug/low power,,,woes. Making a jumper wire and connecting the magneto coils ONE AT A TIME will tell if both coils are good and that the ign module is giving the closed/open required to fire the coil AT TH E CORRECT TIME also.

Pull the connector to the fuel pump.......cannot dump loads of fuel then. DO the starter fluid runability test where you supply all the fuel by little squirts of the go juice on the air filter in the air box. Your unit is FI, therefore NO CHOKE. The original HISUN were carb models then changed to FI. The CHOKE function is now ELECTRONIC which is controlled by input signals from O2 sensor, Engine coolant temp thermistor, Mass air flow and intake air temp along with Throttle position sensor to determine engine load and thus the amount of fuel required for the demand. With the fuel pump disabled, you can then determine your next step.

Ech!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! That's a bummer........had some impossible to service units. Hang in there when getting around to do the tests.

DIODE LEAK......Can be just like a water well foot valve (one-way WATER valve) but instead of water leaking off, electrons (i.e. current) flows backwards thru the diode. They both pass in one (1) direction and restrict flow in the reverse direction. Get sand into a foot valve, water will leak back and loose prime at the well pump......slow leak. Over time the sand leak will cut the gasket resulting in a BIGGER leak. Now the diode......good one passes current (according to the band marking) in one direction WITH a small drop in voltage (0.60V)....thus 12.6v will be 12.0v after going thru the diode. The diode test meter function measures this voltage drop .6v in the PASS direction. The BLOCK direction of a GOOD diode will indicate the same as you never touched the leads (OPEN). Shorted will be way below .6v....like .030V....WOUNDED diode will have a value between open and short (like the grain of sand). Back to Vanguard......simple test of coils and electronic switch........pull the 2 into 1 B&S harness and make a jumper (NO DIODE) and connect to the cover terminal tie node (electronic points) with one end. The other will be put on the individual mag coil terminals (ONE AT A TIME). If coils are good, the respective cylinder will fire and the other dead. Move to the other mag coil lug and that one should run OK. They both generated a NEGATIVE current pulse (interrupted at the PEAK flux and "points" opening have no other leakage paths to GND. The mag coils and flywheel magnet poles are good AND the electronic points are opening at the right time. Now, you have only one electronic switch so the diodes have to isolate PASS/BLOCK WHEN required per cylinder. It might be easier to just buy a new harness as the parts and labor build couldn't be more than $2.00 max.....single one up build....not in qty. purchase prices. Hope this helps this time. Checked out UTUBE....there is a clip showing the harness....no testing, just replacement. check it out.....a picture is worth a 1000 words.

I'll try again........4 stroke V-twin with probably a 90 deg angle between cylinders. 2 rotations of the crankshaft for INTAKE, COMPRESSION, POWER, and EXHAUST. Cam runs at 1/2 speed (2 crank rotations per single rotation of the cam).......therefore, you will have the magnet rotate under the dual mag coils TWICE for each cycle. Timing of the SPARK is req'd around 8 deg BTDC on the COMPRESSION stroke. A single cylinder engine has 1 mag coil and 1 set of "points" (mechanical or electronic switch). The Vanguard has 2 mag coils BUT only 1 electronic switch....that opens and closes in time with 8 deg BTDC of BOTH respective cylinders. The mag coil(s) are "CHARGED" one at a time spaced 90 deg apart WHEN the magnet poles molded into the flywheel pass under the mag coil lamination "legs". The Primary winding has the one end connected to GND. The other end is the side lug going to the points. The magnetic CHARGING causes a NEG (-) current pulse....same as the OLD point system that has to be suddenly stopped by the points OPENING. Think of water hammer when shutting of a sink valve TOO fast. The high tension of the mag coil will pop out 7KV or more when the energy has no where to go when the points open. Testing would be simpler if there were 2 points or electronic switches for the 2 mag coils. COSTS MONEY FOR THE SENSE AND DRIVER/SWITCH COMPONENTS. The combo mag coil primary circuit harness is a 2 into 1 BUT with BLOCKING DIODES. Without the diodes (or a faulty diode) the mag coil ( - ) current pulses will feed each other coil primary resulting in a wimpy weak spark in time for 1 cyl and out of time for the other........BOTH ways as the flywheel rotates under the OTHER mag coil legs. The pair of 10 cent 1N4006 diodes is really a cost savings over having a dual electronic switch ign module. Diode is one-way current valve.....they are both placed cathode to the coil primary spade lug connection. When working, each diode will PASS it's respective ( - ) coil current spike to the electronic switch.........BUT cannot flow backwards (blocked) to the non-energized mag coil and steal the spark generating energy. FAULT results in dual wimpy sparks...1 in time and 1 out of time spark from the other cyl mag coil. The kill wire also goes to the cover connector like before as was on small lawn mowers for the STOP position of the throttle lever. Test the diodes...they may test good and then fail later...that is the way they are with mechanical vibration on the leads (breaks the internal termination to pellet). Easier this time?????

HI there.....not to bust your bubble BUT your problem of weak spark/good spark MIGHT come back when you need it the most. Vanguard is a v-twin with a magnet section molded into the flywheel that goes under the respective mag coil for each cylinder. Go back to the old days when a single cylinder engine was "the" B & S engine. Remember before the electronic mag ign coils??? Under the flywheel and Al lid was a set of points and condenser. The little fiber "points pushrod" that rubbed on a flat spot on the crankshaft arm that opened the points to fire the coil????? The throttle cable "kill switch" that had to be adjusted correctly or it would short the mag coil/points/condenser lead wire to Gnd??? The magnets in the flywheel had to be timed very close to TDC to GENERATE A PEAK MAGNETIC FLUX in the mag coil when the piston came upon TDC on compression stroke..... and......of course the overlap stroke that was wasted. A sheared flywheel key would be a no start/run condition??? Oh, those were the simple days. BUT WAIT, magneto/ignition coil circuit/"points" electronics did NOT change......just evolved into electronic switches to replace the high maintenance points. The low voltage wire from both coils still "need" points......electronic points that is. BUT, on the Vanguard V-twin, they tie together and come out as a single wire to the IGN terminal mounted on the cover. Simple little harness....3 lugs....and a DIODE in each coil leg. The electronic points will "OPEN" at the correct time for BOTH cylinders.......but there is only 1 magnet in the flywheel and 2 mag coils (1 each cylinder). Therefore, only one mag coil can be "charged" at a time (when the flywheel magnet rotates under each cylinder's respective coil)....Sorta the same idea behind car engines up to the late 60's (points cam, external ign coil, and rotor/distributor).....selecting which cylinder gets the spark as needed. Problem is, EACH of the coils primary currents need to be ISOLATED during it's time/turn for a spark output to get the FULL or max current then cut OFF quickly. DIODES to the rescue!!! DIODES-----one-way electrical valves----current only flows thru diode in one direction Diode polarity(s) in the harness is Cathode (silver band on black plastic body) to the mag coil terminal. Both Anodes (the opposite non band end) tie together and go to the "electronic points" cover connector. The coil current is a NEG pulse generated by the rotating magnet poles that gets cut off (OPEN by the electronic points)----like the old days----The mag coil has to be OVER the magnet poles on the flywheel to generate the "energy"......actually a magnetic field in the coil and laminations. Thus the coil can only fire when rotated over the flywheel magnet poles AND when the "points switch" OPEN. There is only one flywheel magnet section. Thus,the mag coils are energized at different times (V angle) and a NEGATIVE current pulse flows from each mag coil lug AT IT's CHARGING TIME.....thru the DIODE.....then to the electronic switch cover connection.....a CLOSED electronic switch that OPENS at peak for the spark at the correct timing(s). DIODE FAILURE MODES: Blown open....no spark on dead section coil. Other coil has spark. SHORTS......will have spark at both coils BUT wispy weak---thus fouled plugs. WHY? Well, the system has to mimic a mechanical set of points......CLOSED for PEAK coil current when mag coil is over magnet poles....then......OPEN at the desired ign timing point say 8 deg BTDC.....Primary mag coil current at MAX then a sudden break in current (magnetic field energy collapses across the HI side coil winding=high voltage spark on spark plug lead). With a harness diode shorted, the sudden "point open circuit" has the primary winding of the OTHER coil drawing current (NO ISOLATION or back feed) that "drains" the energy slowly (wispy weak)instead of a rapid coil current cut off (hot spark). HARNESS DIODE TEST: Pull the covers to expose the ign coils and the simple 3 lug harness. METER ALERT!!!! Digital meter with DIODE test function req'd. Si diodes have a front to back resistance of very LOW R in one direction to HIGH R...>500K or "open circuit". Diode Test function runs about 1 ma DC thru tested diode. GOOD DIODE.......Meter will indicate .6 in forward [red (+) to Anode (non band end)] and black (-) to band end. Reverse leads on diode under test....should show same as before making the connection (OPEN). SHORTED DIODE.......0 or very low .0002 number BOTH DIRECTIONS. OPEN DIODE.......HI resistance both ways....same reading on meter with leads in open air. I like to then go from DIODE FUNCTION to 500K Ohm scale, wet fingers and hold meter leads to diode leads with wet fingers of both hands....should see around 200K ohm...then open one set of fingers and remove your body resistance from the circuit....just a simple test to make sure the meter is working.....should show open. FINAL WORD ELECTRONIC PARTS CAN WORK AND THEN FAIL ONLY TO COME BACK AGAIN AND WORK. These are the worst to T/S and of course NEVER FAIL when the customer is trying to show how it fails...been there?????