atc200s problems

[hessianmx111]

Alright my uncle just bought a 1985 atc200s, it will start fine with a brand new plug in but after you kill the engine from then on out you have to bump start it, and the plug is fouled, its a dark oil coating on the plug, so i was thinking it was the jetting so what should i do to fix it like what size jets and everything to order. the air filter was also an unimaginable mess, as soon as i poured kerosene on it and try to squeeze the old solvent out it fell apart in my hands. any help would be greatly appreciated. :)

[Tweeked]

hey,
I don't know if I'll be much help but i'll try..

I've got an 84' 200es so we'll be on a similar page...First off, I had the same problem (fouling plugs), but it wouldn't start PERIOD. First off, I replaced the filter with a K&N filter, that helped allot. Then I fiddled with the Air/Mixture skrew and did plug tests until I got it to the right mixture. Ever since its been awsome and hasn't fouled any plugs...I'd also reccomend letting it warm up to regular engine temp before giving it allot of throttle, that also fouls plugs.