2-cycle engine quits when hot

May 13, 2007 6 Replies

Hi,



I have a McCullogh weed whacker that's about 9 years old. It's been running fine until the end of last season. Since then, it developed a problem where it quits when hot. It also wouldn't run with choke in "warm" position - it seems to, well, choke whenever I push on gas lever. It does run with choke in "cold" position - until it dies.



I suspected that I had a bad fuel mix, so I replaced it with clean, well-measured fuel / oil mix. Also, the governor screw had a notch on the end from many years of work, so I turned it by 1/2 turn. Nevertheless, it still quits. Any ideas ?



Thanks !!!



I'd clean the cooling fins real good - and the air filter - then try it again. Have you adjusted the carb jets ?

Srgnt Billko wrote: ...

Ditto that. And don't monkey with the carburetor.

Two years ago I took a old mower to the local repair shop. Some kids were assigned to make it run continuously but they failed 3 times. There was lots of adjusting of the carb screws but nothing helped. Finally, on the 4th trip the old guy that owned the shop spent about 10 minutes and had it running fine -- he just cleaned the fins with an air blast. Total: $64.

Dirty fins lead to overheating. Clean with detergent, hot water, tooth brush.

Have a service person take a look. Being that old it could be several things and you might just be better off replacing it.

You might check the 'spark suppressor' screen on the exhaust. I had one that got loaded up with carbon, and it acted like you describe.

G

I fixed a chain saw once by scrapeing the spark arrestor screen, opening up the holes in the mesh. It made a huge difference.

Bob

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