Snowmobile help


Old 02-13-19, 03:10 PM
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Snowmobile help

I have two snowmobiles a 1986 Yamaha phazer and a 199x Yamaha Vmax. They ran good when bought but after a while they were notably going slower. They both start and run. They run high rpms and go around 20-30 mphs at full acceleration. Phazer has a new belt, havenít gotten around to changing plugs. Vmax had plugs changed last season. Where can I start for troubleshooting?
Old 02-13-19, 03:53 PM
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Sounds like either the belt or clutch.
Old 02-13-19, 04:02 PM
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I used to own and ride snowmobiles quite a bit, although that was before either of these were even a vision let alone on the drawing board, and the issues that I recall most common then, and suspect to be the same today, were spark plugs, fuel, and subsequently carburetors. Using that as a premise, unless you know for 100% certain that it is fresh, I would ditch the gas, including completely draining the tanks and carburetor bowls, and would replace the spark plugs. If that didn't resolve the problem the next thing I would do is disassemble, clean, and reassemble the carburetors. Personally, I would not try to "get by" with spraying carburetor cleaner into the carburetors because the ports are so small and the duration at which they set unused is so long that varnish can build up in the darndest spots, so complete overhaul is, in my opinion, the only way to reach it.
Old 02-14-19, 06:41 AM
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Make sure you're using non-ethanol gas if at all possible. When putting them away for any length of time, drain the gas and run the engines out of fuel. Old ethanol gas is known for gumming up everything, especially carbs/injectors. Also, take a look at the variators, making sure they are operating as they should and clean.

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