Surging 2005 RMK 900 Cutting Out

[Mech Engr]

still running badly

Well I'm still at it trying to get this thing to stop surging. I've tried everything. TPS, TPS harness, fuel pump/regulator/pick up assembly, stator, capacitor, ecu wiring harness, ecu, voltage regulator...am I missing anything? I've gone through MH's entire spare stash and can't figure it out. Eric (MH) and I took it up in the deep powder last week and it ran fine for about 10 miles then quit on him. I thought we were going to have to leave it there but Eric managed to limp it back to the trailer. I took it out a few days later and finally got it to throw a code...TPS. Found the new $40 pigtail Polaris sold me had a pin that was sunk in so I fixed that and cleared the code but it was still surging and backfiring. I just changed the stator out last night and started it up to day and it's still doing it. Eric is stumped too. Tomorrow was my last chance to take it out for the season unless we have a miricle storm in NorCal. I was thinking of doing the top end this summer. I really wanted to have the surging fixed before I put it away for the season. Maybe going through the motor might catch whatever it is?? I hope.

John

 

[sartysrnr]

Im sure you probably already checked the throttle safety switch?Crank out of phase maybe?

 

[Mech Engr]

Yea checked the switch. Seems to run really rich when it's surging.

 

[sloan188]

if you think the surging is related to an air leak, you can do a leak down test or run the engine while spraying it (carb cleaner, electrical contact cleaner, etc...) and see if the RPM changes.

I have had an air leak on my PTO seal in the past due to breaking a belt and the belt wrapped behind the clutch and broke the seal. The engine didn't surge at all....pretty much a constant 4000 RPM.

 

[05900]

Have had throttle switch issues there are two in housing and housing ovaled out ~
Exhaust temp probe would "stick" at around 3`` something and never move ~
Ck fuel pressure while it is stumbling before and after...
Stator would kill cylinders intermittently ( gnarly sidehill of course ) had a rivet in it !!
TPS harness and TPS itself~

 

[sleddude]

Cutting out

Not sure if you fixed your problem yet. Looks like you've tried a lot so I'll just let you know what I found twice. My exhaust valve solenoid went bad on my 06 900 causing it to cutout and surge pretty fast almost like it was over reving. This was at around 6500 RPMS and I could hold the throttle right there and it would surge and cutout. I bypassed it plugged the hoses. One other problem causing it to cutout was a loose black plastic piece on the fuel pump was loose super glued it on and hasn't been a problem since. That was bad at about a half tank fine at full tank. Usually when going uphill so gas would move to back of tank and then it would starve for fuel.

 

[mountainhorse]

I've been out for a ride on this sled... and have been kibbitzing John on potential fixes.. one of the most confounding problems I've run across.



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