Tecumseh 8HP Motor Surging - Carb Issue? - Snowblower Forum : Snow Blower Forums
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post #1 of 31 Old 12-03-2016, 02:46 PM Thread Starter
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Tecumseh 8HP Motor Surging - Carb Issue?

Hey all,

I have been having a ton of carburetor issues. I could not get the Tecumseh motor in my Toro to run clean, not stall, not run without choke...whatever. I finally took a chance and bought 1 of the $15 Carburetors off eBay. Before installing it I swapped out (2) O-rings, the bowl gasket and bowl jet gasket with OEM Tecumseh replacements. I reinstalled the new carb and filled with fresh treated gas. The snowblower started right up and seemed ok with each turn of the choke. With the choke off, the motor started to surge and pop and wouldn't stop. The bowl jet was turned out 1.5. No adjustments here did any good. The screw on the side (Idle mixture?) was 1 turn out. Adjustments here didn't seem to do much. I did notice gas coming out from the choke plate prior to starting. Gap on the float looked to be within Tecumseh specs though. Any thoughts?

Last edited by ts8169; 12-05-2016 at 09:24 AM.
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post #2 of 31 Old 12-03-2016, 03:14 PM
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Bowl needle was at 1.5, did u adjust it while running full throttle?


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post #3 of 31 Old 12-03-2016, 03:36 PM Thread Starter
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Yes, the bowl jet/needle was 1.5 turns out. I adjusted from 1.0 to 2.0 turns out with no noticeable difference in the motor. All at full throttle.

The motor did start up for the first time in 9 months - first pull. Can't be too bad.
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post #4 of 31 Old 12-03-2016, 03:49 PM
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Tecumseh 8HP Motor Surging - Carb Issue?

When I installed new eBay carb I put the governor linkage in wrong hole. It ran but surged. Also, loosen the low adjustment screw and see if it runs different (side screw not bowl )



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post #5 of 31 Old 12-03-2016, 04:30 PM
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I chased a problem like this not too long ago on a Tecumseh HM80 snowblower engine.I was convinced it was a carb issue.Come to find out,the engine was old enough to have points/condenser and they were both shot.

Another time I found out that the new sparkplug I installed was just as bad as the old plug.

Ever checked the valve clearances on your engine?
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post #6 of 31 Old 12-03-2016, 05:07 PM Thread Starter
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My engine is also an HM80. Based on the serial number on the blower, it's a 1990 so 25 years until my problems started. I don't have enough skills to check the valve clearance but have watched video's on youtube to see how it's done. I definitely do not have the special tools. What are points/condensers?

My problems all started after I left gas in the tank all summer, then started it in the fall. Was kicking myself. After that when I pulled the carb bowl and saw the mixture of super rich fuel & water, tah dah... So I always assumed it was that carb. I've changed the spark plug, fuel line, cleaned gas tank with carb cleaner, changed multiple parts to the old carb, and now the new carb. Muffler is toast but I can't see that causing issues other than noise.

Before I pulled the old carb, I marked the hole for the governor, then soaked the carb. Guess where my mark went.... I'm about 99.9% sure it's correct though.

Last edited by ts8169; 12-05-2016 at 09:26 AM.
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post #7 of 31 Old 12-03-2016, 06:34 PM
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Tecumseh 8HP Motor Surging - Carb Issue?

Points/condenser is like the coil, builds up power for spark from magnets on the inside of flywheel, unfortunately the flywheel needs removal to do this. Take off starter cvr, take off flywheel nut, take a prybar and apply pressure to back of flywheel, and tap end of crank shaft with hammer.


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post #8 of 31 Old 12-03-2016, 07:55 PM
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Quote:
Originally Posted by ts8169 View Post
My engine is also an HM80. Based on the serial number on the blower, it's a 1990 .
I believe points ignition stopped in the early 1980's, so your motor is solid state with no points to worry about.

If your carb is spitting gas from the carb throat, there is a good chance your intake valve is not seating completely. Checking the valve clearance as recommended earlier is a good place to start trouble shooting the poor performance.

Toro 8/24 (38080) 1989
Toro 721-QZR (38743) 2015 (Hemi Predator Power)
Toro 421-E (38585) 2008 (New Owner)
Experience is something you don't get until just after you need it.

Last edited by Grunt; 12-03-2016 at 08:02 PM.
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post #9 of 31 Old 12-03-2016, 08:03 PM
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Might have to check that, my dad bought a new tecumseh in roughly 92, and it had points. I know this because I used this same eng on a snoblower just few years ago now, had no spark, I got it own to points, change it all out, got it back together, still nothing, turned out it was arching out on the ground wire. That was my first points job, didn't know to check that first! Lol


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post #10 of 31 Old 12-04-2016, 09:39 AM
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Easiest way to tell if it has points. Check the parts list for the engine in question, or pull off the recoil shroud and see if the coil is mounted above the flywheel. If it is, the ignition is solid state.

Toro 8/24 (38080) 1989
Toro 721-QZR (38743) 2015 (Hemi Predator Power)
Toro 421-E (38585) 2008 (New Owner)
Experience is something you don't get until just after you need it.

Last edited by Grunt; 12-04-2016 at 01:26 PM.
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