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Discussion Starter · #1 ·
when my sled sits in the shop and i take it out it runs fine, when it sits out in the cold and i warm it up to ride it runs almost like it has a governor, it hits 5000 or 6000rpm and shuts down till u let off the throttle, eventually after warming up it will run fine, the colder it is outside the longer it takes Any ideas guys? only thing ive did is unhook the pressure line to the DPM manifold and removed and blocked the main DPM lines to the carbs and jetted down. More info on properly removing the DPM would be appreciated too, it would flood itself instantly before i unhooked the DPM and i jetted down because of steady fouling plugs
 

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Discussion Starter · #2 ·
k lets start over we rebuilt the engine and right off the start it flooded itself steady, the only way it started fine was to unhook the pressure line to the DPM manifold. then it ran ok, still rich, we didnt mess with the roatary valve or anything in the stator. if the DPM cant make your sled run rich then what could it be?
 

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may be a stupid comment but along with the engine, have you gone through the carbs. My 98 MXZ 500 was a plug soaker too. Ran fine in he shed wouldn't want it too idel very long for fear of fouled plugs. Had no top end and if you got that far without it happening would soak as many plugs as you had - eventually. Fast forward to December '06 - completely disassembled carbs, cleaned in an utrasonic heated bath, dried, reassembled with new proper (original spec'd) parts - new pilots, correct mains, proper fuel air mixture. Starts on second pull. Idles great - ran it up a little and it seems to have plenty of top end. Guess what I'm saying maybe it isn't the DPM at all might be carbs and if it is - carb cleaner won't cut it so if you can get the carbs professionally cleaned - do it. Cured my issue and I was ready to unload it because of the constant headache. Just a thought
 

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do a complete carb tare down and clean
new plugs
new fuel
retry

Why would you get rid of the DPM?
 

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Thats what I was thinking why would you want to lose the DPM
although I have heard about the DPM tubes iceing up
 

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Discussion Starter · #6 ·
hey sorry i work in the bush and didnt get a chance to check back, the only reason i was gonna remove the DPM is that was the only way it seemed to run OK. i hooked it back up now and same thing it wont even run with the line from the air pump hooked to the manifold. so i thought possibly i had the vent line and the line from the air pump mixed up, running better but not like it should. ive did all the usuals had it out on quite a few runs without DPM so its not fuel or plugs. been there did that. anyone know which line goes where between the vent line and the air pump line?
 

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See if you can find a DPM to try, also check with a Doo dealer on the hook up of buy a service manual.
 

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from the DPM manifold (left side of sled - facing forward)
a) far left hand tube goes to the left side of the carb on the PTO side
b) next one over (2nd from left) to the left side of the carb on the mag side.
c) next one over (3rd from left) to the right side of the carb on the PTO side
d) last one goes to the right side on the mag side carb.

Check for cracks in the lines or possible a crack at the barbs were the tubes go on
 
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