1991 venture 485 wont pull over 5k rpm

03viperguy

03viperguy

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Aug 9, 2003
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Alton, NH
seems to stumble, then run great, then hits a wall and starts to bog and just generally crap out around 5k rpm. cleaned the carbs, twice. brand new plugs. trimmed the wires back and reinstalled the caps. fresh gas. it had sat for 2 years I think in an enclosed trailer. has pretty good compression, 145 and 138 so.... thoughts? seems to be running on the pto side intermittently. when I pull that cap it sounds a little different, but much worse if I pull the mag side cap. with the plugs in the caps to check for spark it seems to have plenty.I seem to find a few other threads on other forums with similar issues, but no listed fix. thanks guys!
 
think it could be? seems more like it is flooding out. I will pull the clutch and check it though. anyone happen to know if it is the same puller that I used on the viper?
 
couldnt hurt.

But if you think its flooding, does the carb have float needles that could possibly be worn out?
 
the needles seem to be working correctly. they arent rubber, solid metal with no grooves
I was thinking, the sled ran just fine before being put away, so I feel like the clutch can be ruled out. I think at least. seems like either fuel or electric.... is my logic solid?
 
so after I replaced the coil and plugs it runs exactly the same. anyone have thoughts about rust on the flywheel? had a mech friend say that was an issue on other sleds he had seen. anyone heard of this?
 
yup, no difference with it hooked up or bypassed. had the same thought. kind of stumped with this little fan motor....
 
check the choke plungers along with re-thinking your carb cleaning procedure.

there are three orifices/jets on the carb throat air box side. one or more of those are most likely plugged. one leads to the pilot jet, one to the main jet, and the other will slowly exit the overflows. all need to be clear, meaning something enters something exits be it carb spray or compressed air.

depending on your fuel choice, even sitting for two weeks can cause issue.
 
the carbs are clean, carb cleaner and compressed air through ALL passages. wonder about the choke plungers though. should I just make sure they are adjusted right? never had issues with them before so I havent needed to fool with them
 
check the rubber plugs that cover the center hole and pilot jet hole if they are hard or not in the right position that could very well be you problem .......then it comes down to plugged pipe plugged airbox or reeds ............but most likey a carb issue if all else has been checked
 
I had wondered about hose plugs. they seem to be in there, and are still there when I take the carbs apart again. maybe they are leaking a little? the thing snaps great on the the low end, just completely dies @ 5krpm
 
My guess is clutch as well. I just had to take mine apart and clean it up. Mostly due to lack of use.
 
Have you pulled the plugs after running it wide open (even if it only reaches 5000 rpm) for a while just to get an indication of what is going on fuel wise?
 
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