[polaris_xc_racing]

My sled acts like it is not getting fuel. It has spark and compression. Both cylinders fire but on the PTO side there is nothing on the plug, but it is firing. The only way to get the sled to start is but dumping gas into the cylinders and even then it's a PITA to keep it running. It runs like complete crap and we tried to see if it would move and it shot up to 5000 RPM's and didn't want to go, put it on a track stand and got it to go. What could be a possible solution to this? I just pulled the VES valves they need to be cleaned bad, maybe this has something to do with it? I took the fuel pump off to check and make sure it was ok. Maybe I messed up there? I should add too that it will only stay running by touching the throttle, let it go and the the idle drops and it wants to die.

 

[jesse500]

your carbs clean? no clogged/broken gas or air lines? are you reeds un-damaged? did you check everything like an unclogged airbox, un cracked carb boots, etc.....


I agree, sounds like it is starving for gas. But you say there is nothing on the plug? Like it doesnt get black or brown? Then there is no oil, or not enough in the fuel charge, So I would check your oil lines, and oil pump setting and the whole pump itself.

 

[polaris_xc_racing]

Nothing on the plug, I was wrong though it is not the PTO side (not sure if it makes a difference) PTO side plug was fine. Looked for cracked carbs boots they're still good. Will check on that other stuff. I tried like crazy to get that airbox aparts but damn it's a bitch on this sled. I have the reeds off to be cleaned, I'll take a picture of them when my camera is done charging and post it.

EDIT: To answer your first question yes, carbs are clean. I cleaned the carbs and ended up with a bunch of problems. Makes sense right? Fix one thing to ruin something else.

 

[BskidooC]

Sounds like a needle and seat to me. Possibly a fuel pump problem but not likely since your getting fuel to one cylinder. Could also be your pilot jet, but even then you should still get some fuel in that cylinder.

 

[polaris_xc_racing]

Pretty bad, eh?

I'll have to check the needle and seat, I'm thinking you're right on that. I don't know why I didn't think of that before seeing how I had that issue on my 700 last season.

 

[BskidooC]

They deffinetely have some carbon build up. Is the plug thats not firing wet at all?

 

[polaris_xc_racing]

It was barely wet, I had to look very closely but did see it had a few specs on the plug. They were brown though no white on it or anything.

 

[polaris_xc_racing]

I think I may have found my issue. The line on the bottom of the carb that has the blue plug on the end of it. If that is broken in half like mine just so happens to be that will dump gas out right? I'm thinking thats my problem.

EDIT: Stopped to the local dealer and got some line really quick. Should be back up and running in no time. Thanks for the help everyone.

 

[SnowmobileAddict]

I would think that a big puddle of gas under sled would be a dead give away!

Any time you run the sled or pull it over gas is being pumped into that carb bowl and then dripping out that broken sediment hose. There should be gas dripping out of the bulk head.

 

[polaris_xc_racing]

I didn't see or smell gas dripping under the sled. When did I say I saw gas dripping?

 

[polaris_xc_racing]

Got the drain plugs replaced on the carbs and it runs like its on one cylinder? 120psi clutch side 115psi on the other side. Brake light on the dash flashes when you touch the gas? Electrical issue or time for a rebuild? Or both?

 

[BskidooC]

Thats a big difference. I would say you have a cylinder failing. Couldnt tell you on your light. You still have enough commpression to run the cylinder even if is failing. I would say theres still a problem. I would keep looking into fuel delivery and think about some rings and or pistons before you tear something up bad.

 

[sambell]

That light i believe means its retarding your timeing making run like crap. Why im not shure make shure your carbs are clean that would be the first thing to check.

 

[BskidooC]

ok that makes sense if it has a knock sensor. The sensor may be detecting detonation and retarding the timing(if it has one).

 

[SnowmobileAddict]

If you had a cracked sediment hose on the bottom of one or both of your carb bowls and there was no dead giveaway gas puddle under your machaine then I would say check your fuel pump for a fuel delivery issue among the other housekeeping items mentioned above relating to carb jets and VES valves. Assuming a cracked carb bowl sediment trap hose and a functioning fuel pump, there should have been gas dripping from the cracked sediment hose/drain line everytime you cranked the engine.

Check the pulse line to your fuel pump from the crankcase, the fuel line running from the fuel tank to the fuel pump including the screened tank pickup, inline filter if you have one, fuel shutoff valve, and tank vent. If all of those check out okay I still think that it would have to be a fuel delivery issue with the fuel pump. The pump rebuild kits are ridiculously cheap. They ammount to a couple of die cut rubber diaphragms and some other die cut fabric looking pieces. Wonderful corn alcohol in our modern fuel can damage the pump diaphragms.

Also, see if you can check your compression with another tester. Or use your tester on a "control" test (another sled that you know should produce a compression reading within specs)compression testers are known to be all over the place with regard to accuracy.

 

[polaris_xc_racing]

I was going to get a fuel pump rebuild kit today but I took my plugs in to show the guy I buy parts from and he told me to run a compression test on it first. I should of just ordered one I think it cost me five bucks for a kit on my 700 last year. But I will try and tear into it some more tomorrow.

EDIT: BTW, wow I can't believe I'm going to admit this but we all do things and forget, but I did forget to turn my gas back on because I did have it shut off. I'm assuming that is why I didn't see gas dripping out of the busted drain line. I did clean the carbs, but my parts guy told me to check and make sure a jet didn't come loose or something. I dunno, I will try everything you guys said to do. I did have the sled on the track stand and it will go you just have to get on it a bit.

 

[SnowmobileAddict]

EDIT: BTW, wow I can't believe I'm going to admit this but we all do things and forget, but I did forget to turn my gas back on because I did have it shut off.

Been there done that! Its always fun when you shut the gas off for trailering purposes, then get to your trailhead, start the machine and take off. You end up getting like 150 yards and then the bowls are completely empty when it dies. Then you have to pull the damn thing over like 25 times to re-prime the bowls!


If you are cleaning your pilots note that the hole in them is impossibly small and the screw driver that fits them has to be a good snug fit (they strip EASY) if you plan to remove them to run a strand of wire through to clean them out. If you've done this before, you already know that though...

good luck !

 

[MicahMan]

wow

 

[polaris_xc_racing]

Wow what? Wow that I left my gas off? Ok, my bad, still doesn't solve my problem though.

 

[BskidooC]

Well know that you have gass to the carbs(lol jk). Whats it doing?