I have a 2003 Vinson that has been sitting for 3 months. It started, but when I try to throttle it up it misses, boggs down and dies. It seems to run better with the choke on but still won't take more than a quarter throttle without backfiring and dying.

I've drained the fuel and replaced, changed the spark plug and let it idle for more than an hour and still won't take fuel.

I hooked it up to another battery thinking the battery may be bad but still does the same thing. However, if I restrict the amount of air it is receiving by placing my had almost completely over the intake hose at the airbox it will allow me to throttle it more but still misses and backfires. Any Ideas? I'm at a loss.

 

Could be junk in the carb or the screen where the fuel hose goes into the carb. pull the line off and spray some carb cleaner in the inlet and use a soft wire to clean it out. If that dosen't work you'll have to pull the carb float bowl and clean all the jets.

 

check for a vacuum leak, manifold to engine

 

check for vacuum leak at manifold to engine, spray with wd-40, if idle goes up, replace gasket and check for a cracked manifold