Rural King Hisun 550 UTV timing/idle

[Daniel P]

  I have a rural King Hisun 550 with 16 hours on it  and it seems that the  timing is set too high.  It kicks back when started  cold and it idles too fast.  Also, it seems that the thermostat  is stuck open because it takes it forever to warm up and it never gets to the midrange operating temperature.  I looked at the parts list and didn't see that it has a thermostat.  There doesn't seem to be any way to adjust the idle and it idles too fast to change the gear range or reverse.  I've replaced the fuel injector and installed a fuel filter, that didn't do much.  

[kenfain]

A machine that has 16 hours on it, should still be under warranty. Why not try that first?

[Daniel P]

Hi Kenfain!  It was bought originally a couple of years ago by someone, and when problems started happening, they returned it to Rural King.  It had been setting around for a year or so after that and the store manager wanted to get rid of it, so it sold it to me with a $3000 discount and it doesn't have a warranty.  

 

[kenfain]

I thought it would be something like, that since you're here asking questions about something that definitely should be warranty work. 

Have you checked for trouble codes yet? Strange blinking on the dashboard clock? Anything like that?

Due to the nature of your problem, there's probably not a code thrown. But sometimes you get lucky. And at any rate, that's the best place to start. 

[Daniel P]

Thanks Kenfain!  It is not showing any error codes on the display, only the time and the hours.   I'm thinking maybe the cam timing chain is loose but I don't want to immediately dive into that until I get some feedback from this forum.   I wish I could find a service manual.  I have rebuilt several motorcycle engines and the like, but it would be good to have a manual and parts diagrams to help troubleshoot.  I don't think the engine has a coolant thermostat, at least I haven't been able to locate it.  With a fuel injected engine, things can get funky when the temperature the engine computer senses is incorrect.

  

[kenfain]

Yes, I can see where a loose timing chain could cause the issue. But I'd think that you would hear it making noise, if it were that loose. But at only sixteen hours, it seems unlikely though.

 Unfortunately, if there's no codes, and no way that I know of, without sophisticated testing equipment, to get live data readings. Then you'll probably be left to just test each possible component. Or until more information leads you in a specific direction. 

I think the temperature sensor is as good a place as any to start. But since data for testing each component, seems hard to come by. How would you know what constitutes a failing part, that hasn't actually failed yet?

[Daniel P]

Okay guys, I found the problem on my Hisun 550.  One of the compression release cam plates on the cam chain drive gear came off and fell down into the gearbox and crankcase!  Luck was with me because none of it got caught into the crank or drive gears.  The little torsion spring  must have gotten pinched in one of the gears because it was mangled and cut in two pieces.  I was able to order a cam shaft assembly from Alpha-Sports and have installed it.  But I had to tear the magneto cover off to fish out all of the broken parts from the crankcase, and that took quite a bit of time.  The service manual is a little vague on setting the cam timing.  I found the timing marks on the chain sprocket and camshaft end, but the manual doesn't specify where those are located relative to the head.  After looking at other manuals, I believe that those marks should align with the top center of the head with the piston at top dead center.  If anyone knows different, please let me know.  THANKS

[kenfain]

Any luck figuring out the timing? Seems like there should be another mark on the flywheel or the crankshaft. Something to make certain that it's at top dead center. 

[Daniel P]

Yes!  On the inside of the head housing, behind the chain sprocket cover, there is a little projection at the very top that the timing marks on the cam sprocket and the compression release shaft should be aligned with when the piston is at top dead center.   The magneto flywheel has timing marks on it that lines up with the "peep window (behind the blower) when the piston is at top dead center.   I got the engine all back together and it runs great now! 

 

[kenfain]

Glad to hear it's back in service.