Tecumseh HM80 starting problems Help!

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  #1  
Old 01-07-09, 12:37 PM
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Tecumseh HM80 starting problems Help!

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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  #2  
Old 01-07-09, 02:29 PM
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Sounds like timing, runs like cr*p, glowing muffler. Check the key on the flywheel first.
 
  #3  
Old 01-07-09, 02:42 PM
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I checked the flywheel key and it is fine.
 
  #4  
Old 01-07-09, 02:46 PM
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OK, how about the carb, any adjustments made after the kit was installed?
 
  #5  
Old 01-07-09, 02:50 PM
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Equipment that is infrequently used such as snow blowers commonly have fuel related problems. Fuel, especially in winter climates, can become stale and breakdown into varnish in just a few months.

Fuel that has varnished cannot only damage carburetors but can cause the valves (especially intake valve) to stick in the valve guide.

Did you thoroughly clean the carburetor? Thorough includes removing welch plugs and cleaning the passages behind them. If your answer is NO, clean the carburetor again.

Did you adjust the carburetor per the manual?

Did you use FRESH fuel?

Install a NEW spark plug. A misfiring plug can cause the problems such as you describe.

If you get the engine running, add about 4-6 ounces of SeaFoam to the fresh fuel in your tank. Let the engine run for about 30-45 minutes. I hope that the SeaFoam will help clean any residue from the valves and/or guides.

Try the things I mention above. If you get the engine running then pursue the glowing muffler. Glowing mufflers are a "common complaint" with snow equipment, which after daylight savings time expires, is often used when dark and glowing mufflers and blue flames are pretty normal.
 
  #6  
Old 01-07-09, 06:27 PM
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I haven't had the chance to adjust the carb yet I just turned the main and idle needles out 1 1/2 turns each, I noticed in the Tecumseh manual my carb should start at 1 1/4 turns out so I will set them like that when I get it back together to try.
I always put fuel stabilizer in my gas for my equipment even if I use the fuel in a week, I learned my lesson that you never know when you will have to let your equipment sit for more than 3 months. I have cleaned the carb three times and the last time in a ultrasonic cleaner and the carb has no welch plugs. I have a new spark plug. I have never seen sea foam for sale here in Canada but I can check a specialty store.
 
  #7  
Old 01-07-09, 07:00 PM
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It sounds like you have done all you can with cleaning the carburetor. Ultrasonic cleaning is the best you can do. The Walbro LME is a good carburetor and usually can be restored. Assuming the carburetor is good I suggest you look at the valves. Check intake valve for sticking and check valve lash of both.

If this is an older engine with points then ignition timing could be a factor.
 
  #8  
Old 01-11-09, 04:06 PM
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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.
 
  #9  
Old 01-11-09, 04:36 PM
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The hunting can be gotten rid of by adjusting the fast and idle circuits. As far as the box, they are pretty much all the same less the old style with the throttle on the side.

TECUMSEH CARBURETOR HEATER BOX COVER HM80 Snowblower - eBay (item 150319770375 end time Jan-13-09 16:11:10 PST)

Here is the box on ebay.

The throttle lever should be able to be purchased at a small engine shop.
 
  #10  
Old 01-12-09, 07:36 AM
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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?)
 
  #11  
Old 01-12-09, 07:48 AM
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Originally Posted by aaaaex88 View Post
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?)
3600rpm, vibra tach is the cheapest tool, uses engine vibration to measure rpm. Gearing on the impeller has nothing to do with it, you stated in your previous post that the throttle is only running at 3/4 which will have a huge impact on throwing distance. Also, how old is your 7hp. Are we comparing a 1 year old machine to a 25 year old 8hp?
 
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Old 01-12-09, 08:31 AM
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my H70 and HM80 are about the same age. Even when I hold the throttle to full on the HM80 it doesn't throw snow as far as the H70. I looked at that heater box on ebay but just my luck, I have the throttle on the side so I will have keep my eyes out or build something. Thanks for all you help cpgixxer
 
  #13  
Old 01-12-09, 10:05 AM
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Originally Posted by aaaaex88 View Post
my H70 and HM80 are about the same age. Even when I hold the throttle to full on the HM80 it doesn't throw snow as far as the H70. I looked at that heater box on ebay but just my luck, I have the throttle on the side so I will have keep my eyes out or build something. Thanks for all you help cpgixxer
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Tecumseh carb cover- Heat box HM100 or HM80 snow blower - eBay (item 330300227053 end time Feb-10-09 21:37:25 PST)

Have you checked belt condition and/or adjustment for tension?
 
  #14  
Old 01-13-09, 01:50 PM
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I will check the belt condition and tension, I bet that is it.
I went to a local small engine shop and the service guy showed me what the carb cover for my engine looks like and some one must have changed the throttle and choke levers. That one on ebay looks like it could work, I'll check out how far my choke lever moves.
 
  #15  
Old 01-15-09, 05:34 PM
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This sounds a little like the HM80 on my old Bolens snowthrower. Eventually it lost compression and wouldn't start. Once that happened, I found it had a broken valve keeper on the exhaust valve. I was told when buying the part that this was a fairly common failure. It may not be the most likely cause, but it's easy enough to check.
 
  #16  
Old 01-24-09, 11:55 AM
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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 found a carb cover and with some drilling a filing it works.
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
 
  #17  
Old 01-25-09, 08:45 AM
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Originally Posted by aaaaex88 View Post
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
If I were you i'd just buy a used starter off of ebay, I've got 2 starters in the garage that are in pieces that need armatures, finding them is not going to happen. As far as the recoil is concernced, I think you can get a new spring for them.
 
  #18  
Old 01-26-09, 03:35 PM
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Originally Posted by barryds View Post
This sounds a little like the HM80 on my old Bolens snowthrower. Eventually it lost compression and wouldn't start. Once that happened, I found it had a broken valve keeper on the exhaust valve. I was told when buying the part that this was a fairly common failure. It may not be the most likely cause, but it's easy enough to check.
how do u check if you have a broken valve keeper?
 
  #19  
Old 01-27-09, 06:59 AM
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Originally Posted by poop1 View Post
how do u check if you have a broken valve keeper?
Take the breather cover off and look at the valves.
 
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