Tired old techumseh

Auto Doc's said:

Hello T.,

The HM100 is a 10HP rated engine, but an 8HP would still do the job on a log splitter. These were heavy cast iron blocks and held up very well for a lot of years.

A lot of this depends on matching the crankshaft dimensions. Length, diameter and with or without a taper on the output shaft.

The bolt down dimensions may require that new holes be drilled to mount a replacement engine.

Being that old of an engine may take some adapting. I am still a fan of the old B&S flat head engines for applications like this. They were simpler to work on that the Tecumseh and lots of parts are still available for them.

Chinese clone engines are a big gamble and most compatible Honda GX series engines are just too expensive.

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Rivets said:

Before replacing this old mule I would stick a little time and money into cleaning and rebuilding the carb. Replace the float needle and seat, Tecumseh part number 631021B. I’ve attached the procedure I’ve recommended many times on this forum.

Needle and seat replacement.

Remove the carb, and then remove the float bowl. Check the float bowl jet (which is the bowl screw) and make sure the jets both horizontal and vertical are clean and open. Tip the carb upside down and remove the float pin and float with needle attached. Look in the float needle passage and you should see the red float seat at the bottom of the passage. This is where a #5 crotchet hook would come in handy as you need to remove this seat. If you have no hook, but compressed air, you can blow through the fuel inlet and try to pop the seat out. Put your thumb over the passage to prevent the seat from flying who knows where. No air or hook try bending a stiff paper clip to dig the seat out.

I would either give the carb a good 24 hour soaking or have it ultrasonically cleaned at this time.

With the seat out clean the passage way with carb cleaner. Now you must find a drill bit slightly smaller than the passage way, to be used to press in the new seat. Apply a very, very small amount of a very light lube to the new seat. 3-1 oil or lighter, to help seat it better. Carefully insert the new seat in the passage way with the rings on the seat down toward the carb body. Slowly and carefully force the seat down with the back end of the drill bit. Once it is seated, check to see that it did not flip and the rings are up. Next check to make sure that the float does not have any liquid in it. If it does, replace. If everything looks correct, attach the new needle to the float and install with the float pin centered. It everything is correct, the float should seat level to the carb body, when looking at it upside down. If everything looks good reattach the float bowl, making sure that both the bowl gasket and the nut gasket seal properly. Reinstall on the engine and test unit. Remember to have patience and take your time. Good luck, but I don't think you'll need it.

PS: On the side of some Tecumseh carbs you will find a plastic cover. Under this cover will be an idle jet. Remove it and check to see that the jet is open both horizontally and vertically. You should be able to push the old float needle wire through the vertical opening.

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TFLHNDN said:

I will give this a try. I am all about getting one more season if I can. Even if I can get a few weeks out of it that is a win.

My big concern is the amount of oil it burns.

I'm still considering getting a backup motor so if this one goes down I have one on hand for a quick replacement. Our primary heat source is wood so Murphy would say the motor will go out at the least convenient time i have a decent stockpile and I can always split with an axe but the log splitter is so much easier on the body.

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TFLHNDN said:

First time posting.

I have a log splitter that is pretty old. Not sure exactly I bought it at a garage sale and have gotten 5 good years out of it with a lot of tlc. It has a tecumseh hm100 motor. Last year the carburetor started giving me problems and I limped it through the winter. This fall it will not start and I'm considering a new engine vs. replacing the carburetor.

It burns quite a bit of oil and I'm constantly adding oil while working. The carburetor was pretty dirty when I took it apart and I cleaned it out. The spark plug was full of carbon, more so than last year.

Any thoughts from the community or suggestions for a replacement motor are appreciated.

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