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Craftsman 8HP HM80. (1978)


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08-16-09, 07:55 AM   #1  
Craftsman 8HP HM80. (1978)

Yes, this is the same snowblower from 2 years ago. I used it last season, went well.
I got the rim / tire issue done too!
Now, the govenor seemed to work itself loose. I have the manual and tried to put it back to stock. It starts well, idles well, but the RPM is way too fast. I can have the idle at 1/2 and it's good. After that, the engine is way too high on the RPM side. There is no surging, or stalling just to much speed. Both engine and carb are Tecumseh units. Which screw(s) do I need here???

 
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08-16-09, 02:26 PM   #2  
If you have the manual it shows how to adjust the high speed RPM's, If the governor is adjusted per the manual and you still can't get the RPM's down to normal there is most likely a problem with the governor it's self.

Without a spec. number posted, I cant tell which throttle control assembly you have.....

 
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08-16-09, 05:18 PM   #3  
The numbers are:
Sears Craftsman - HM80-155137C
Engine - 143-666322
Ser - 6243D

It seems like the govenor is not sensitive enough? The plate on top of the carb has the linkage in the middle hole / stock.
After 1/2 throttle, the engine RPM speeds fast. There is no regulation at all. I believe the govenor is set correct once again at the base in front of the motor.
The high speed screw on the bowl is at 1 9/16 from seated.
The low speed mix screw is at 1 1/4 from seated.

 
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08-16-09, 05:49 PM   #4  
The mixture screws have nothing to do with the RPM problem you are having, The linkage in the middle hole could/would affect the RPM's.

This is not your carb set up I know but the most common used hole is the one nearest the carb throttle shaft, If it were moved to the next hole shown it would rev higher than normal;




Try moving the linkage and see if that helps.


Good Luck

 
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08-16-09, 05:57 PM   #5  
Great picture - thanks.
I'll try moving the linkage the other way and see what happens.
Cheers.

 
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08-17-09, 06:35 PM   #6  
I moved the linkage back one hole and it help a lot. I was able to keep it running without over revving. Now it seems a little slow on high. I tuned the carb in 1/8 turns for low speed - works great.
Same for high speed under the bowl - not bad.
It starts well after shut down so no flooding. I think I need to move the govenor linkage a touch away from the carb.??

 
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09-17-09, 06:59 PM   #7  
Thanks.

Thanks again for everyone's help. It's running good now and sounds good too.
Cheers guysBeer 4U2

 
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