1999 Kawasaki Mule 2500 617cc Smoking Engine

[Mikey]

Just bought a well used 2500 with 6,800 hours on the clock. Guy said it had a bad engine but it did run and drive when I tested it and it billowed white smoke. I found oil in the water and a disconnected fan switch. A compression test yielded 160 psi in one cylinder and 240 psi in the other. I put 15 psi in the cooling system and it dropped to zero in 30 seconds.  I removed the spark plugs and put 100 psi of air into each spark plug hole and coolant few out of the uncapped radiator. So I figured I had two bad head gaskets.

I took the heads of the engine and found two bad head gaskets. Cleaned them up, checked for cracks, found none and reassembled with new genuine Kawasaki head gaskets.  Started engine and it ran well but smoked constantly at idle and at full throttle. Comprression test now yielded 240 psi and 245 psi which is higher than I have ever seen in any gasoline engine I have ever tested. I put 100 psi into each spark plug hole and no water or air bubbled out of the open radiator cap. When I put 15 psi into the cooling system it held pressure. Also fixed the fan switch connection and installed a digital temperature guage so I know exactly what temperature the engine is seeing and that the thermostat and cooling system is functioning properly.

The engine smokes like it is worn out and needs overbored but with those great compression numbers it is had to believe. I am ready to pull the engine and tear it down but thought I would post to this forum before I did.

This is my first Mule. I only paid $800 for it and might decide to just part it out depending what I find inside the engine. Brakes are good, trans works fine and there is almost no rust anywhere.

Any advice will be greatly appreciated.

Thanks, Mike

 

[Travis]

Welcome! 

245 pounds??? Thats odd, is this a FD620 engine? The spec is 170 psi. For that engine.

You can also find rebuild kits with oversize pistons for around $250

 

[Mikey]

Yes that is wierd. I can't explain it. 

I got the the engine out and apart this morning. Everything looks really good with the exception of the flywheel side crank bearing which is badly worn especially on the top. I figure this was due to the previous owner running the engine with a lot of water in the oil from bad head gaskets. I will obviously need to replace that bearing and was figuring at a minimum of a new oil pump and new piston rings but am debating an overbore job and oversize pistons only because of the difficulty in finding a reputable place to bore it correctly and turn it around in less than 6 months. Guess I'll make a few calls on this.

I will also test that compression tester guage against another one I have and verify that it is reading correctly but I wonder if that is somehow part of my smoking problem. Doesn't make sense.

Thanks for your comments.

Mike

[Travis]

 

Post some pictures of the cylinders, how do they look? it's possible you might could squeeze by with new standard rings and a hone job.

I used your location and i believe this machine shop is in your area, they seem pretty good. https://www.facebook.com/donsautoparts

 it would be best to have a professional measure the cylinders to determine wear on them.

 

 

[Mikey]

Thanks Travis. Here are some pics of bores, pistons and flywheel side crankshaft bearing.

Dons is a quality machine shop but works mostly on cars engines. I have had machine work done there before but like all machine machine shops they make mistakes especially on things they do not do often and their wait time is long and hard to define.

I am thinking that I will just install new std rings, replace the bad crank bearing and install a new oil pump and go. Regarding honing, some folks say that will remove the special surface treatment on the bore and not do do it. I am planning on not honing.

I did verify that my compression guage is reading accurately. I am most disturbed that I can't explain those high (240 psi and 245 psi) compression numbers on a seemingly worn out engine. Do you know if the valve timing marks should look like in the pic below? Seems right to me but I don't have my service manual yet.

Do you happen to have the spec for piston ring end gap?

Thanks, Mike

[Travis]

There is only special surface treatment on Aluminium bore engines (such as Nikasil), not Cast iron sleeves. You can hone the heck out of a iron bore engine.

If you put new rings on the slick wore surface you will have a very hard time to the new ones to seal .,

timing marks are correct.

you should be able too get specs you need by calling or e mailing Kawasaki with your Mule or Engine model.

[Willy M]

If you have coolant in the oil you need a rebuild, no telling how long it ran with poor to no lubrication.

[Mikey]

@Travis Thanks. I did not realize the engine had a sleve in it but checking with a magnet verified that it does. Guess I will do a hone  with a drill job on it and put in new rings. I am thinking the stone kind of hone instead of the flexible balls on springs kind of hone. Do you have experience with either or both and can recommend one over the other?

[Mikey]

@Willy M Agree, I am just trying to decide how much to rebuild. The minimum is new std sixe rings and new crank bearings and probably a new oil pump. Thanks, Mike

[Travis]

I use the 3  stone hone, but the dingleberry hone as I call it provides a better crosshatch  pattern, the stone hone seems to leave a coarser finish.

It mostly comes down to what you want to pay for one.

And try to get your rod bearing clearance spec and check with plasti gauge. Videos all over youtube how.

And definitely order new rod bolts, don't want to skip on the bolts that literally hold the insides together.

When you do hone have the internals of the block all out, don't need dirty homing residue anywhere. It's like sandpaper.

[Travis]

8 minutes ago, Travis said:

I use the 3  stone hone, but the dingleberry hone as I call it provides a better crosshatch  pattern, the stone hone seems to leave a coarser finish.

It mostly comes down to what you want to pay for one.

And try to get your rod bearing clearance spec and check with plasti gauge. Videos all over youtube how.

And definitely order new rod bolts, don't want to skip on the bolts that literally hold the insides together.

When you do hone have the internals of the block all out, don't need dirty homing residue anywhere. It's like sandpaper.

And you definitely want a bottle of Permatex assembly lube, a good torque wrench,shop rags, and several cans of brake parts cleaner. You want those cylinders SQUEAKY clean after honing.

And another thing is check for up and down play on the Rod small end and wrist pin. Side to side is okay .

[Travis]

Another thing i would recommend for at least the first oil fill, use the correct weight, probably 10w40 for yours, not sure. but use the Kawasaki K-TECH oil, it has higher levels of Zinc (zddp) and phosphorus and other anti wear additives which have been almost erased from modern automotive oils because of the E.P.A, which is not good for small engines with flat tappets. If not buy a zddp additive.

[Mikey]

@Travis Many thanks again. Will do.

Also, thanks for the psot the other day about kawasakipartshouse.com. That is where I bought my engine repair parts from. Good prices. Shipping isn;t the fastest becuase I guess they do not stock the items themselves but not bad. A good value.

Thanks again, Mike 

[Travis]

Another good thing to do will be to pull the valves out and lap them, gives them a new sealing surface and helps form a tight seal when closed. It's not 100% necessary, but on an engine that old it's will not hurt a thing in the world.

[Travis]

Any updates @Mikey?

[Mikey]

On further inspection of the cylinder walls after dingleberry honing (which worked really great by the way) I saw one cylinder wall has some distress most likely caused by water sitting in the cylinder of a year or more. It was difficult to see withou tmagnification but it was there and it was significant. So I will receive one .020" oversize piston tomorrow then run the new piston and block up to Millenium Technologies in Plymouth, WI to overbore the bad cylinder. I'm sure this is where the oil burning was coming from. 

Regarding the 295psi compression test the only area of heavy carbon deposits or any deposits in the cylinder for that matter was in the dimples of the exhaust valves. They were complete filled in. Now that they are cleaned out and I am anxious to take another reading.

I used this down time to clean and coat the inside of the gas tank, bleed brakes, install new tires and repaint.  Looks like the engine will go back together the first week of Sep and I should be back on the road by mid Sep. Will install a windshield and roof top too.

Thanks for the follow up.  Mike

[Travis]

Cylinder looks nice!!!  Great job.

Do you have the original standard cylinder specification?

[Mikey]

No I do not have any specs. I ordered the manuals and they are due tomorrow.

[Travis]

You'll have to give the machinist the original standard spec so he can bore out what would be .020 over from the bore brand new.

I'm sure you knew that, but I'd hate to see anything go wrong on an engine build.

[Mikey]

@Travis  Thanks. The piston comes with the bore info per pic.

Looks like bore needs to be 76.50mm or .050mm larger than piston diameter.