Outdoor Power Equipment and Small Engines - Need help with a Tecumseh HM 80

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View Full Version : Need help with a Tecumseh HM 80


Rocketsauce
03-12-06, 04:20 PM
I have recently ran into a problem adjusting the carb on a tecumseh HM 80. I installed a new carb kit and I am not sure if the power screw on the bottem of the bowl is set right or the mixture screw on the side of the carb. If anyone has any suggestions on rough setting please let me know. As of now there is also a rpm surging of my motor when it is running at full idle. Is the a possible governer problem and if so what can i do to correct it? Thanks :wall:


mla2ofus
03-12-06, 04:50 PM
IIRC lightly seat both screws and back out 1 1/2 turns on each. this should give you a good point to start from. If it still surges at high speed, turn bottom(main) jet out(counterclockwise) in small increments to see if it smoothes out. if it starts blowing black smoke, turn back in 'til black smoke goes away. Float level could be set too low and yes, there could be gov linkage binding someplace. I would try the main jet adjustment first and work from there.
Hope this helps,
Mike

Rocketsauce
03-13-06, 08:50 PM
Thanks for the advise Mike. I have tried backing the main jet out slowly but cannot find a spot where it runs good. Today i bought and installed a new main jet assembly and replaced the mixture screw this helped a little bit but it is still surging unless the choke it turned to half and other suggestions? Thanks


Rocketsauce
03-13-06, 08:51 PM
also wondering how to set correct float level?

mla2ofus
03-13-06, 09:08 PM
Someone correct me if I'm wrong, but I believe the float should be parallel to the carb body with carb body upside down It sounds like this could be the problem. Also check to be sure of adequate fuel supply from tank to float needle.
As long as you didn't remove the gov arm from the shaft coming out of crankcase and the gov and throttle kinkages are connected as they were, this should not be a part of the problem.
Mike

Rocketsauce
03-13-06, 09:15 PM
Thanks I'll check it out tomorrow. And let you know.

cheese
03-14-06, 01:18 AM
Sounds to me like the carb has a restriction and needs cleaning.

puey61
03-14-06, 04:06 AM
When Cheese says cleaning, he means in a quality bath type cleaner (I like Napa's # 6401). Be sure to remove all rubber and most plastic items from the carburetor first though as they'll be ruined if allowed to soak in this solution. Use protective gloves and eyewear when handling this as well.