2000 Summit 600 Flooding Both Carbs - Snowmobile Forum: Your #1 Snowmobile Forum

Alaskan 007 · 01-29-2008, 06:42 PM

I pulled it off the trailer, fired it up. Parked it, got dressed, went to go riding and it was pumping so much fuel into the cylinders that the plugs were getting soaked, and fuel eventually started dripping out of the airbox!! The next day I pulled both carbs off, cleaned and thawed them. Put them back on...no change. I'm wondering if it might have something to do with the DPEM which, among other things, controls the fuel/air mixture for elevation, temp, etc. It is odd that both carbs would act up at the same exact time with the same exact symptoms. It acts like the choke is stuck. But if that were so it would still fire up when cold right (Plus I thoroughly checked the carbs)?

Well, I have VERY strong spark and compression so the electrical system all together isn't to blame. Does anyone have any experience with the darn computers on these things? Thanks

**smallengineguy** · 01-29-2008, 07:51 PM

Unplug the DPEM solenoids when it's running and see if it stops overfueling.

Alaskan 007 · 01-29-2008, 08:31 PM

It won't run because the plugs get so wet from fuel coming in. I just got it in the garage to warm the whole thing up. I'll see if it'll start when warm. Any other thoughts if it won't run?

**smallengineguy** · 01-30-2008, 07:31 PM

Replace the plugs with new ones. Try NGK Br9EIX Iridiums.

Alaskan 007 · 01-30-2008, 08:32 PM

So much fuel is getting pulled through the carbs that a brand new spark plug won't fire off, and I've got good spark. When I pulled it over with no plugs in it sprayed about a half a cup onto the engine and floor. Not the wet mist you usually get. Something is telling it to pull way to much fuel, or can't stop the flow from the fuel pump. Leaning more toward the computer...I don't know if they normally act up or just quit on you. I tried talking to my local dealer but couldn't get a live person!!! It would be nice if I could take it in and have them test the unit.

Alaskan 007 · 01-30-2008, 10:35 PM

After talking it over I recall that when I had the carbs off fuel would not stop flowing out of the lines that feed the carbs. I had to raise them to a high enough elevation before they would stop. That makes me think that the fuel pumps is letting fuel blow right past it. Does it sound to anyone that the fuel pump might be the problem?

**smallengineguy** · 01-31-2008, 06:57 AM

Fuel WILL come out of the lines, even with it off. It's up to the carb needle/seat/floats to shut off the flow when not needed. Have you replaced the needle/seat yet?

Alaskan 007 · 01-31-2008, 10:51 AM

I have not. Does it seem strange that both carbs would act up at the same time? Thanks for the help and discussion by the way.

**smallengineguy** · 02-01-2008, 07:20 AM

The pump's job is to get the fuel there, nothing else. It's up to the carbs to shut it off. You can have the needle/seats pressure tested. They should hold 5lbs pressure.

Alaskan 007 · 02-01-2008, 09:13 PM

To bring some closure to this thread for the sake of people who have this problem in the future:

After I had the sled inside for a few days I was still getting tons of fuel out the spark plug holes. I now realize that it was coming from all the excess fuel pooled up in the crankcase. After it sat longer it stopped spewing fuel, and I could see that there was no fuel moving through the lines into the carbs. After talking with the local dealer I replaced the fuel pump and I'm back in action.

The way I imagine it is that ice got sucked into my fuel pump and stuck it open, causing the massive overfueling. Then when I warmed up the sled the ice thawed, but had ripped a diaphram in the pump giving me no fuel to the carbs.

**smallengineguy** · 02-02-2008, 06:32 AM

Wow! Strange outcome! Good catch!

maineack bob · 02-02-2008, 08:18 AM

I had the same think happen to my Indy XCF last winter it took me almost 2 weeks to solve the problem... gas in the base can be a real nusence.