Hello,

I am new to this post, and new to snowmobiling all together. I just bought a 1988 Yamaha Exciter 570 cc and the plugs are fouling up on it. I bought new plugs and it ran good for about 1/2 a mile and then it bogged way down. I shut it off and came back home and it bogged down then I let it go down and gave it more throttle and the rpm's would go up but only go about 1 foot and bog down again. He said he had older gas in it up to 3 years but he said he added new gas, I put in my own 2 cycle oil, and greased everything up but whats going on? The drive belt seems to be a little tighter than what it should be also could that do it? I am getting fustrated with it, I know its an older sled but it runs fine for 1/2 a mile and the plugs are all fouled up. I would appreciate all the help I can get. Thanks for your time.

First empty the tank of gas. This means take the tank out and dump it out and clean it. Then check the fuel strainer in the tank and the fuel filter. The reason it is runniing good and then not is because the sediment relaxes in the tank and lines- when its not running. Then when you start it up again it sucks all the crap back up and clogs the lines again.

it could be your coil as well, first i'd do as the others said and then go one step further and clean your carbs with all that old gas they'll be tarnished up for sure.

I would also clean the tank, replace all the lines and fuel filter, plugs and drop some new fuel in it. Fire it up and see how she goes