Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

Hello Folks,

I have an older tecumseh hm80; the engine is running rough even when warm.  I need to keep the choke half-engaged in order to avoid stalling the blower.

I drained old fuel and replaced plug;  dirty carb-choke or points & timing?

Regards

Frank

Fdease,

Its running lean, try to adjust carb.

Try it with the fuel cap loose.

Sometime lack of venting will cause  the problem that you have.

                                               Fred

Thanks Fred.

Am I looking for two adjustment screws on the HM80?  Also, I think its misfiring a bit, short flames are coming out of the exhaust

Regards

Frank

Frank - If loosening the fuel cap didn't work, turn the high speed screw on the bottom of the carb "bowl" counterclockwise a 1/4 turn & see if it runs better. If not, try a 1/2 turn. If it still needs the choke to run, remove the bolt on the bottom of the bowl - its the one that the high speed screw bolts into. You will lose some fuel so have a catch can or rags handy, and either shutoff the fuel valve or drain the tank before starting. Once the bolt is out, observe it & look for one or two small holes:

These are almost always the culprits causing lean running conditions. Grab some carb cleaner & a wire bread tie. Carefully run the wire thru the hole or holes until you can see the wire on the inside center of the bolt. Then spray well with carb cleaner. Repeat the wire chasing & spray cleaning. Install the bolt. Turn the high speed screw in lightly until it stops, then back it out 1.5 turns. Fiddle with the adjustment until it runs well. You may have to play with the idle mixture too to get it 100%.

Marty