rough running 300 enticer

[woodsrider]

My daughters 300 has been in storage for 2 years and when started today it wants to idle fine. Mid range seems good but WOT is very rough, almost as if it is too rich and can't quite clean or lean out. Pulled the carb out and inspected everything and it appears fine. Main jet was clean, and all ports were open. Any ideas? New plugs, fresh fuel, Can this be a timing issue? Not sure if this model had problems with stator or not.
Thanks for your ideas!

Woodsrider

 

[snowdad4]

couple years stored where? ran across this problem once on a stored cat. something made a nest in the pipe. remove the pipe and see if it responds to wot, however, be careful not to overdo it as you dont want to suck any cold air back into the cylinders. hope this helps

 

[Maim]

check for sticking primary clutch weight. also check the wires from the stator where they come out from the housing. i have heard of them rubbing the wires through there and causing a problem like you describe.

 

[woodsrider]

rough running 300

Thanks for the suggestions guys!
I will check all of the ideas and let you know. The most promising is the muffler as the sled was stored upstairs in a dairy barn that does have red squirrels in the winter. So last year, since it wasn't used the squirrels could have made a nest there, and in the air intake. I'll check!
Merry Christmas

 

[woodsrider]

rough running continued

I have now checked the muffler- it was clean! Checked out all of the wiring, it looks perfect. The strange thing is the engine pulls in sync perfectly from idle to about 3/4 throttle. Which is where it starts to run rough. The more you run it the more it seems to load up even at a lower rpm. My next thought is a fuel pump diaphragm issue. Any chance it could be leaking fuel back into the crank as the crankcase pulls a vacuum?
Woodsrider

 

[Maim]

hmmm doesnt sound right to me. did you change fuel filter while you where at it? our et250 blew the pump diaphram. but it filled the crankcase with gas when motor wasnt running. i would think it would do the same thing and it wouldnt run at all. check the vacume line from the crankcase. might be split too.