# Tecumseh HM80 starting problems Help!



## aaaaex88 (Jan 7, 2009)

I have a tecumseh HM80 that is now on a different snow blower. I got it and it ran but not well, it backfired and kept dying. I cleaned the carb (walbro lme) and installed a carb kit and now it will only run at half speed for about 5 seconds once then it won't restart. I had it running with a spark plug from my other snow blower but before I fine tuned the carb I wanted to change the oil because there was gas it in and I noticed in my dark garage that the muffler was glowing red. I pulled the drain plug and since the oil was so cold I let it drain over night. The next day I put in a new spark plug, 5w30 synthetic oil and changed the diff oil. Thought I was ready to go snow blowing but I won't run again. I did the same thing, ran at half speed for 5 second then died. I need help.


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## dj722000 (Oct 29, 2008)

Hmmm, good call on changing the oil. I kinda think your carb is a little dirty or set wrong. Id pull the bowl again to make sure nothing came in from the tank and got sucked into the carb.. If some stuff came from the tank to the carb, clean carb again. I would also pull the tank, flush it out and put it on again. What did your spark plug look like? Was there black gunk on it, black carbon on it, little tan? Black gunk, bad rings or cylinder, balck carbon, carb set to rich, light tan, it should be good to go. Tell tale signs of something bigger or if it is running ok. If your muffler is glowing red, kinda sounds to me like your exhaust valve is sticking a little too. Which can give your backfire you describe and keep it from running good. You can put some sea foam or Marvel Mystery Oil in the fuel to help free up the valves. This should give you a start.


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## aaaaex88 (Jan 7, 2009)

I will give the tank a cleaning, soap and water good enough?
The old spark plug didn't seem too bad, it was dark but not built up with carbon or oil, I had a spark from it but the spark didn't look like it was always happening from the tip to the tip but I replace it with a new one. I have never seen sea foam or Marvel mistery oil here in Canada, maybe I will check a specialty store. Just before I drained the oil the engine was running good so I am still confused. The compression was around 80 psi, the exaust port was black but it didn't look like there was any build up of carbon, and I sprayed combustion cleaner in there and let it soak for a while. I have cleaned the carb three times already, the last time in a ultrasonic cleaner but I guess I will have to clean it again after I clean the tank.


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## geogrubb (Jul 28, 2006)

Usually after all the cleaning and stuff the problem is the bowl nut(main jet) which looks like the picture below, some have holes only in the bottom, some have a jet screw throught them but they are the problem, so clean all the holes you can find, I use the wire from a twist tie for the tiny one, then blow out the holew with brake parts cleaner. Have a good one. Geo
http://i190.photobucket.com/albums/z120/geogrubb/tec_bowl_nut.jpg


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## dj722000 (Oct 29, 2008)

(Bangs head off desk) Cant believe I didnt say that. Thanks geogrubb. A big reason it wont run. I guess I can say I said it when I said clean the carb. LOL.
Yes you can use soap water, just rinse and dry it out really good so no water in it. Personally I would use carb cleaner and spray a bunch in the tank and dump it out. Make sure your fuel line is clean to. Did you by chance mark your linkages when you removed the carb? Also, the little passages dont take much to get plugged if everything isnt cleaned. (Tank, fuel line etc) So you may end up cleaning a few times. I believe your on the right track here.


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## paulr44 (Oct 14, 2008)

dj722000 said:


> (Bangs head off desk) Cant believe I didnt say that. Thanks geogrubb. A big reason it wont run. I guess I can say I said it when I said clean the carb. LOL.
> Yes you can use soap water, just rinse and dry it out really good so no water in it. Personally I would use carb cleaner and spray a bunch in the tank and dump it out. Make sure your fuel line is clean to. Did you by chance mark your linkages when you removed the carb? Also, the little passages dont take much to get plugged if everything isnt cleaned. (Tank, fuel line etc) So you may end up cleaning a few times. I believe your on the right track here.


*Reminder*

Soap and water...good to use, but engines don't like water in fuel. We have K&N air filters on several lines of machines, for which SOAP and WATER is recommended, but I tell customers to LET THEM DRY OUT overnight on a radiator.

*DJ* - how's your head?


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## dj722000 (Oct 29, 2008)

LOL Its ok paulr44, just a little dizzy from the medication. Havent been feeling myself lately or as far as that goes, (Upper Respiratory Tract Infection) havent been feeling much of any thing lately. LOL


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## aaaaex88 (Jan 7, 2009)

I cleaned the fuel tank out and noticed the rubber tube at the bottom of the tank was sticking up a bit so i might not had enough gas in it. I got it running but the engine hunts a bit but not too bad.
I have two small problems now.
1: I don't have a cover on the carb and snow is getting into the intake and making it run bad so will have to make a box or something.
2: The throttle lever won't stay at the fast position, the vibration from the engine moves the throttle lever to about 3/4 full position. Is there any way to fix it? The bump that fits into the notch must be worn.


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## dj722000 (Oct 29, 2008)

I know on some of these Tecumseh engines they will hunt a little bit if not under load. Once under load it should purr like a kitten. Yes definitely fabricate a box to go over carb so no water gets suck into carb. Not good if you just spent all this time cleaning it out. As far as the throttle goes, is there maybe a little nut on there you can tighten up so it doesnt slide around? Or if there is a rivet maybe a set of channel locks and squeeze the rivet tight around the linkage arm to keep it from sliding around? Just a few thoughts....


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## aaaaex88 (Jan 7, 2009)

What is the rpm supposed to be?
What is the best low cost tachometer I can get that works?
The snow doesn't seem to fly as far as my 7 hp H70 snowblower and want to find out if it is due to low engine rpm's or gearing in the impeller (can that even be adjusted?)


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## geogrubb (Jul 28, 2006)

You can get a Treysit Sirometer(vibration tac) for about $12 it will get you within 100 rpm, it's Tecumseh part# 670156. Have a good one. Geo


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## dj722000 (Oct 29, 2008)

Engine wise, High RPM, I would guess around 3400 maybe a little higher. I think max is around 3600.
Adjustment on gearing, probably not. Unless you change some stuff. Maybe a slipping belt on impeller when under load? As far as it not shooting the snow out far enough, how much rust is in the auger housing and impeller housing. If there is alot of rust it will slow it up a bit. To much friction. I dont know what kind of snow blowers you have if they are even identical. If not, then there probably powered (as in pulleys or what nots) differently causing the difference.


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## aaaaex88 (Jan 7, 2009)

A slipping belt, didn't think of that, I will see if it slips by having the tensioner engaged and try to turn the belt by hand. There is a bit of rust but I don't think enought to slow it down but I will check that too. They are both Ariens snowblowers but the good one is a few years newer maybe a 9000 series, the one I am working on is from 1968.


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## paulr44 (Oct 14, 2008)

Like DJ says, you may have to increase the rivet tension on the throttle control. Assuming it's the engine mounted style, he's correct that it's a rivet, but I doubt you'll be able to use a channel-locks to tighten it up. I take them off, and take it over the the vise so I can put the rivet onto the anvil or a punch in the jaws and hammer a bit on the rivet head, with hopes of tightening it up. I'd say you have a 50/50 chance of tightening it up.


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## aaaaex88 (Jan 7, 2009)

I now have a functioning snowblower, thanks. I tightened up the throttle by using a punch and a hammer on the bump so it now stays at full speed with out slowing down and I replaced the belt so snow shoots out a bit further.
I have an anoying problem with the shoot moving on its own and not blowing snow where I want it to. the crank handle only needs to be turned about 3 to 4 times to go from side to side but it won't stay in the position I set it at. Is there a way to tighten up the shoot? I also must have over used my starter because it won't operate very good any more. I took the starter apart and measured resistance of the comutator bars and most are open so does anyone have a good used armature for sale so I can get the starter going again? Along with the starter not working the pull cord started not recoiling very good. I guess I will have to take that apart now. Will it ever end with this snowblower? LOL


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