9 Horse Tecumseh kicking my a$#

[linrick1]

Hi everbody, I recently got my hands on a very nice early 80's Simplicity 870 snowblower with a Techumseh HM-80 in need of a little TLC. I have already repaired/adjusted everything needing attention on the chassis and then started on the motor. I rebuilt/cleaned the carb with new needles and gaskets, cleaned the fuel tank, replaced the fuel line and installed a fuel filter, changed the plug,etc., etc. and of course it still wont run as it should. If I have both the main and the idle jets backed way out it will run at very rough high idle but backfires through the carb or the muffler depending on how the needles are adjusted-I am out of ideas here and could use some help.....Thanks in advance, Rick

 

[Craig Clayton]

Have you checked the points and condenser, that involves pulling the flywheel. The float setting in the bowl could be low. I was taught to set the idle screws as turn to bottom then back out 2.5 turns and then fire it up. Fine tune it after that.
Craig Clayton

 

[mark1]

I too worked on many of those old Tecumsehs.a bad set of points will have you pulling out your hair. Pop the flywheel,replace the points & condenser.

 

[ToadHill]

You might also check the key on the flywheel, if it is bent just a bit it will throw the timing off and result in the kind of issues you describe.

Over the years I've had at least 5 or 6 small engines on equipment that I bought for a song because the engine was "shot" and a bent or broken flywheel key was the only thing that kept it from running.

 

[linrick1]

Thanks to all for the quick responses. I removed the motor from the snowblower, brought it into the shop where I removed the recoil and the shroud with the intention of popping off the flywheel to work on the points and condenser. Apparently Tecumseh uses a plastic fan assy. that I am not at all familiar with - do I remove this plastic piece to access the holes for the puller? How does this come off without damaging it? It would appear that it just snaps into a groove machined the outer edge of the flywheel, no? Again all help is appreciated, Thanks, Rick

 

[ToadHill]

If all else fails take 2 large screwdrivers and put pressure on each side of the flywheel. Put the large nut back on and smack it with a large rubber or plastic hammer. ( Or as my English friend says "address it smartly").

In my experience the flywheel will pop loose.

 

[linrick1]

If all else fails take 2 large screwdrivers and put pressure on each side of the flywheel. Put the large nut back on and smack it with a large rubber or plastic hammer. ( Or as my English friend says "address it smartly").

In my experience the flywheel will pop loose.

LOL! "address it smartly"! Thats exactly what I'll do in the morning.....thanks,Rick

 

[KubotainNH]

Sounds like the carb has a plugged jet or orifice somewhere. Typically if the motor will take off with a squirt of starter fluid or gas straight into the carb then the issue is in fuel delivery.

Hopefully no one was inside the engine deep enough to make the cam timing off.

 

[Tig]

Could you post a good close up of the carb. The Techumseh's I've owned had an amazingly simple carb. It had a very fine passage from the fuel bowl to a draw tube in the center of the bowl. That passage would get plugged and was very difficult to spot if you didn't know it was there. The fix was to pluck a bristle from your wire brush and poke the hole clear.

 

[linrick1]

Little update...Got the flywheel off, purchased replacement points and condensor, was turning the crank through by hand (with the plug out) and it felt as though it was binding for like an eighth of a revolution so now must investigate this......awesome. Its a series 3 carb and you can see it pretty well in an above pic. I was informed about that miniscule passage and believe I have that cleaned out too...Rick