[mckinnri]

Hey everyone, I'm new to the site but have spent alot of time reading posts from others. Looks like their are many knowledgeable people here which is great. I'm currently searching for help with my sled which I suspect might have one foot in the grave. It'll start right up with new plugs (and choke) it won't idle and after a couple seconds will cease to accelerate and I can hold the throttle wide open with the engine "idling" only. Pulling the plugs reveals the left one dark and wet, (gooey tar) the right one just wet. I've cleaned the carb adjusted idle and air/fuel screws to no avail. I even took the middle idle screw right out with no change.(ie: it still only idled with throttle wide open) I observed some dark discharge from the bottom side of the exhaust manifold and saw some oily residue below the engine. (looks like it might be leaking around the head gasket area) but I know nothing about snowmobile engines. I haven't checked the compression yet but I suspect it's okay since it ran last year. I'm perplexed and very depressed since we just got a bunch of snow overnight and today......................I'll keep looking through posts to see if I can learn more.

 

[brandcole73]

Is there spark on the cylinder that has the oily plug? Check both for good spark. Sounds like maybe the one isn't firing.

 

[mckinnri]

Would that cause it to "refuse to rev" when the throttle is held open? i'll check it tomorrow. I bought a new spark plug "cap" for the right side but the left one is older. I could replace it as well I guess. But I'll check for spark first. Thanks

 

[RJ Gleason]

Check the exhaust for any obstruction (mouse house).

Welcome and Happy Trails

 

[brandcole73]

Not sure about the symptoms, but with that much build up on the plug, sounds like it's not firing all the time. My XLT wouldn't rev up when I had one cylinder go down from a cracked carb boot. But it acted boggy and wouldn't idle either. Not to cause you any worry or anything...

 

[mckinnri]

okay thanks. I should have mentioned that my son has already had the sled out a couple times this year. A total of about 4 hours. He got stuck after the sled bogged down and stalled. I looked at the plugs and both were black and gooey, burnt. I put new plugs in but that didn't help. It lasted 15 min before the plugs fouled out. I pulled the carb and blew it out. There was not gunk whatsoever inside (it was fogged in the spring). Tried adjusting the air screw to 1 1/4 turns out with the idle screw at 2 to 3 turns out. right now, i could remove the idle screw (larger one) completely from the carb while it's running and it wouldn't change a thing. The sled is stored indoors, so out of the reach of mice.