# Not enough revs under load



## BlueBlackBird (Jan 22, 2014)

Hi, Tecumseh HM80155169E, Starts 1st pull, adjusted all the jets after carb rebuild, but it just seems that under load and full throttle it is revving low.I can still blow but to me it sounds like I need more RPM. I have repositioned gov. arm either too much revs or just a bit low. I have read posts here if that engine runs too fast it can blow a rod or magneto. So I am timid to have it rev too high. Could this be a governor adjust problem? or?? How high(rev) is too high. I do have a tach/dwell tester. Thanks


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## scipper77 (Dec 4, 2013)

Sounds like your problem is that it is bogging more than you think it should. The first thing I would do is check compression. I'd think a number higher than 80 psi would be good but to be honest I really am not sure what is an appropriate spec for that motor off the top of my head.

Over reving the motor is not something you should ever have to do.

Also since you have a tack/dwell tester (I have one too) you can verify your current RPM's. Should be 3600.


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## motorhead64 (Dec 15, 2013)

Your rpms should be 3600 with no load. You can expect a drop of 200 or more rpm under load, even after the governor kicks in. Overspeeding a Tecumseh engine can cause a connecting rod to break. MH


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## BeerGhost (Dec 17, 2013)

try setting the governor according to the tecumseh service manual

http://dl.dropboxusercontent.com/u/12502267/Tecumseh/Tecumseh L-Head.pdf


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## mtd1024 (Feb 2, 2014)

motorhead64 said:


> Your rpms should be 3600 with no load. You can expect a drop of 200 or more rpm under load, even after the governor kicks in. Overspeeding a Tecumseh engine can cause a connecting rod to break. MH


why would it cause a connection rod to brake?


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## scipper77 (Dec 4, 2013)

mtd1024 said:


> why would it cause a connection rod to brake?


The force of the piston changing direction puts a strain on the rod. The faster the motor spins, the greater that force is. At some point something's got to give. Also heat builds faster at higher RPM but then you get into the whole discussion about air cooling and the fan needing to run faster to carry off heat.


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## cdestuck (Jan 20, 2013)

You might try opening up the main jet a 1/4 turn at a time and diving into the snow. Sometimes it sounds like your carbs adjusted under no load but needs more fuel when you hit a load.


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## BlueBlackBird (Jan 22, 2014)

Thanks, I do have the Tec. engine tech manual on my desktop, and I will try the govenor adjust with very small increments. Also open the main jet under load 1/8 turn increments. Thanks for the replies. By the way I have only used the tach on my old 73 750 Honda. How do I connect it to the Tec engine??


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## scipper77 (Dec 4, 2013)

If it's like my dwell meter it will have a setting for different numbers of cylinders. I can't remember if it uses and inductive pickup or some other means. Whatever result you get you will need to multiply by 4 or 6 or 8 to get the correct number of rpm's for a 1 cylinder.

I'm going on a foggy memory here, you may have to divide. Whatever gets you to a reasonable rpm reading.


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## threeputtpar (Jan 16, 2014)

The two machines that I tinkered with this year both had the same symptoms. Rebuilt and new carb didn't help, so I checked valve lash on both and they were all in spec.

Both machines did have carbon build up in the head and one had a sticky intake valve. After cleaning them up real well, they run like champs. Don't forget to get new head gaskets if you're going to go this route.


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