Snowmobile Running Rich??

[reddeerguy2015]

Hey guys,

Got a 98 polaris triple, 2 stroke.

Fresh top end rebuild, about 5 hours on it.

Sled seems to be running very rich with choke all the way off. Bogs, pops, farts, backfires and hesitation - until she catches, then she runs like a raped ape.

Seems to get a bit better when she's fully warmed up, but far from perfect - still getting a hesitation in low rpms, bogging down....then she catches her breath and WHHHHHHHAM!!! About 110mph in 6 seconds.

Starts in 3 pulls with full choke up to -20. Run it like that for about 30 seconds to a min, then switch her over to half choke and she'd run all day on half choke if I let her.

Only problem is when it warms up it idles better with no choke, but that damn hesitation, burping and farting when smashing the gas.

Jetted too rich ?? What say you 2-stroke wizards.

- running premium fuel (no ethanol)
- always run seafoam in the gas (for last 3 years)
- shell 2 stroke oil (most expensive stuff you can buy from Canadian tire)
- carbs are clean
- did the same thing before top end build, although seems more noticeable now ??
- brand new irridium spark plugs
- air intake not blocked or restricted

Help.

[IL Bar]

To me it sounds like an issue with pilot jets. Might be on the lean side. Have you cleaned carbs yourself to know they are clean? What color are the plug tips after you ride it for a bit? Are they blackish, light brown, or whiteish?

[reddeerguy2015]

Originally Posted by IL Bar

To me it sounds like an issue with pilot jets. Might be on the lean side. Have you cleaned carbs yourself to know they are clean? What color are the plug tips after you ride it for a bit? Are they blackish, light brown, or whiteish?

Good question. Will report back tomorrow with an exact answer.

[reddeerguy2015]

Actually just reading around online, seems backfiring can be a symptom of a lean jetting condition??

Does this seem right gurus ??

[reddeerguy2015]

Okay the more reading I'm doing on this, the more it seems to point to a lean running condition.

Which would make sense, as I melted the top end down last winter doing a bunch of wide open runs across the hay field.

Sled is oil injected (seems to be working, at least at an idle as it's a smoke show when started and idling).

Water pump and coolant is good (mechanical gauge tapped into cooling rail by heads, doesn't seem to get much hotter than 130 degrees running in powder). Seen it get higher on hardpack but not much.

So where do I start ?? Main or pilot jets ?? Carb boots leaking ?? How can I test this ?? Maybe spray ether around the carbs and see if the sled revs up while idling ??

[JustBen]

1. Stop running seafoam in every tank. Only run it if it needs it. Maybe once per season.
2. Do a plug chop. Best way to determine if you are rich or lean. You should be able to review your current jets against recommended for your altitude and get an indication.

[Lites out]

Check the color of your plugs as mentioned! Lien sounds more likely than rich. Will only take a 10min jet change to rectify! Pull airbox to get to bottom of carbs.Take apart bottom of carbs and remove jets with jet wrench or small socket. post which size of jet youre running and I can probably help as I use to own lots of polaris triples