Got given a trail boss and cleaned it all up. pulled carbs and cleaned all fuel system components. Started it and idled for about three minuets then backfired and stalled. It will restart but runs really rough. Some tips on where to start the troubleshooting process would be great.

It sat for about five years before I got it if that is of any use. Previous owner loved it but bought an new one and just left it to die. So sad.

 

Collectors item if you have a 1980 model The 350 was made from 1990 to 1993. Start first with a compression test. Sitting five years neglected is bad on any engine especially a two stroke. Crank seals can soften with gas left in the crank case and leak also making starting and running right almost impossible. Plus you need a good manual on this engine. Here's a pdf link. http://gh-ftp.com/ORV%20Manuals/Pola...0All%20Models/

 

I don't know where my head was last night. Tired I guess. It is a 1991 trail boss. Thanks for the tip and will do a compression test today. If compression is good how does one check to see if the seals are shot?

 

Leak down kits are the only way to test seals,gaskets,etc for any problems. It's cheaper just to pull the flywheel and stator and the front drive clutch to be able to get to them and just pop em out and knock in new ones.I can almost imagine what they look like after 5 years of sitting.

 

Thanks. Since you are an expert and I a novice will do as you suggest. No sense dicking around and have them fail later if this is not the problem. The rest of the machine is now in good shape as my brother in law and I have torn the rest of the drive system and suspension apart and freed it all up. I think it is worth the effort. | may attempt this myself and may have a tech do it. Could you give me a rough idea of the hours a tech might charge. I really appreciate the help so far.

 

Labor is the cost as the seals are only about 8-9 bucks a piece. Just a generalized guess,most shops would charge 2-3 hrs at their hourly shop rate.Each shop is different. If you have the time you can save some bucks by doing it yourself..

 

Thanks so much. If a shop is two or three hours for a guy that knows what he is doing i should be able to do it in a day in my garage. Like so many things, the first time takes way longer but a project I think I can handle.

Thanks again.

 

I have a copy of a CLYMER shop manual for the 1991 trail boss (not 1980, dumb *** and have reviewed the procedure for removing the flywheel. Seems simple enough. There is nothing mentioned in the manual about the seals but i assume the seals you refer to are on the crank and located behind the flywheel.

Is it a single seal or are there multiple seals? (seems unlikely on the crank but hey, what do I know)

Is this the only seal I should be concerned with?

 

#4 and #7. One's behind the front clutch(7),one's behind the stator plate(4). Dirt Cheap Yamaha, Honda, Arctic Cat & Polaris OEM Parts & Accessories – Cycle Parts Warehouse Just pop out and install the new ones.

 

Start with the seal behind the drive clutch first as it's the one most prone to leakage seems like,plus I've found em half way out. If it still has problems after this,then you may have to replace the seal #4 on the crank case and the outer #4 seal behind the stator. If you have to go this far I'd replace the w/p seals and bearing. This can be labor intensive on this engine.