DPM/HAC issues

[Jmcelley]

Please help.

I have an 03 Ski doo Summit 600 HO that won’t rev under a load. It will hit 7000 rpm then won’t rev unless you choke it or but then backfires after.

It starts and idles fine even seems to run fine on the stand in the shop. Carbs and fuel pump are clean, new fuel tank gasket and fuel screen. Compression may be low but it’s the same on both cylinders. 88 psi. Sled only has 900 original miles on it. Hate to get rid of it but supper frustrated with it.
Tried different plug wires and coil. Didn’t seem to help or hinder.

Been reading on deleting the hac/dpm? Has anyone done this? If so can you point a guy in the right direction. This is not the rev chassis

 

[BBP]

Don't delete the DPM, they work good. Check that your rave valves aren't stuck shut. If you had the secondary clutch apart, did the spring get pre-tensioned? Broken primary spring? Could also be a sticking DPM solenoid. Unplug it & touch 12 volts to the contacts. You should hear it click if it's working.

 

[Jmcelley]

Dpm solenoid is working, I did the 12v test. Primary spring is not broke as we took it off and check it. The rave valves seem to be fine. I did take them out and cleaned them up. It’s a head scratcher for sure.

 

[NEWDUCK]

That compression is very low. Might be why it cant pull itself when it gets a load on it. If you are wondering if the dpm is doing anything un plug it and run it. Then youll see.

 

[Jmcelley]

It runs better with the dpm unplugged but still wouldn’t run at elevation. It ran pretty good at home 4800’. But wouldn’t rap out at 10000’. I did change the jetting so I’m not sure if that would of helped anything.
After i checked the dpm solenoid I plugged it back in and it ran worse.

 

[BBP]

The dpm should have no effect at idle. if idle changes when unplugging dpm, then I would focus on the dpm. Solenoid can be bad & still pass the click test. Something plugged in the dpm? Vent line to dpm kinked, or full of fuel?

 

[BBP]

Whatever you do, don't lean out your jetting to compensate for a bad DPM. If it starts to work again, you'll smoke your motor. Been there!

 

[BBP]

It runs better with the dpm unplugged but still wouldn’t run at elevation. It ran pretty good at home 4800’. But wouldn’t rap out at 10000’. I did change the jetting so I’m not sure if that would of helped anything.
After i checked the dpm solenoid I plugged it back in and it ran worse.

I just reread this. I missed the part about 10,000 ft elevation. You're probably clutched too heavy for that elevation.

 

[Jmcelley]

It never had an issue at elevation before though. Last year the pilots were plugged then the pilot jet broke off trying to get it out. Had to take the carbs apart from each other and put in another carb of the same in.
air screws were replaced and carbs were set back to “stock” settings.Starts and idles fine. Just won’t kick into High gear under a load “so to speak“.

 

[retiredpop]

It has to be something with clutching.
Check your setup with the chart found here for your sled.