# 8 HP Tecumseh runs rough



## Gib Pierlot (Oct 24, 2007)

I have a 8 HP Tecumseh on my snowblower. It starts easily and runs smoothly at low rpm but if I advance the throttle quickly it starts to miss badly and can't recover. If I slowly advance the throttle it will accelerate fine and run smoothly. Can anyone give me some advice?


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## glenjudy (Aug 26, 2006)

Make sure the air filter is clean. What is condition of spark plug ?? make sure it's clean and properly gapped, .030.
You didn't give model and spec of engine, it carb has nut on bottom, loosen and let fresh gas and any sediment drain. re-tighten.
Other than that, an old fashioned carb disassemble and clean will likey take care of your problem.
hope this helps.


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## Gib Pierlot (Oct 24, 2007)

Thanks for the reply. I bought the snowblower used and I can't find a model number anywhere. It has the John Deere name on it. The engine has no air filter, just a metal housing that encloses the carb and the bottom portion of the muffler. The carb does have a nut on the bottom, with a screw through it and a spring on the screw. The previous owner said he had just had a tune up including a carb kit. The fuel line had no filter so there could be dirt in the carb. Any idea why it runs fine if I accelerate slowly but starts to miss if I push the throttle too quickly?


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## glenjudy (Aug 26, 2006)

The screw on the bottom with the spring on it is the main jet adjustment. Assuming carb and jets are clean, screw it in finger tight, turn it out 1 1/2 turns. Usually if it stalls on fast throttle-up, the main jet should be opened a little more. get engine running and turn this main jet screw 1/8 at a time, may have to close it as well, after trying fast throttle-up. Even tho previous owner may have put kit in it, it may have been unused long enough for fuel to get gummy.
Some, maybe most, snowblower motors don't have air filter, since there ain't much dust around while blowin' snow.
hope this helps,


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## engine man (Mar 25, 2006)

most tecumsehs are known to run rough and are hard to fix that problem. tecumsehs in my life are the crappiest engine ive ever seen. buy a briggs and you will be much happier


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## Gib Pierlot (Oct 24, 2007)

glenjudy said:


> The screw on the bottom with the spring on it is the main jet adjustment. Assuming carb and jets are clean, screw it in finger tight, turn it out 1 1/2 turns. Usually if it stalls on fast throttle-up, the main jet should be opened a little more. get engine running and turn this main jet screw 1/8 at a time, may have to close it as well, after trying fast throttle-up. Even tho previous owner may have put kit in it, it may have been unused long enough for fuel to get gummy.
> Some, maybe most, snowblower motors don't have air filter, since there ain't much dust around while blowin' snow.
> hope this helps,


 Thanks for the advice. I tried adjusting the jet and it didn't solve the issue. I removed the carb bowl and it was clean there. Maybe I'll have to live with accelerating slowly, it runs beautifully if I do that. Gib


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## JerryinWI (Oct 25, 2007)

Snowblowers as a general rule don't have air filters. Pull the carb bowl and clean it and the needle. It is probably varnished up. When you reinstall it, screw in the needle all the way then back it out three and a half turns. Once you get the engine running you can adjust it while the engine is running at full throttle. Adjust so you have a smooth running motor at full speed. Dump a half can of SeaFoam into your gas tank and let her run for a half hour. Remember to purge the gas in the spring...store it dry.


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## 30yearTech (Sep 14, 2006)

Whats the model and spec number of your engine?

Sounds like you may have a restriction in the low speed circuit of the carburetor, not giving you the extra fuel you need for acceleration. If this is the problem then you may also notice it when you are using it and a load is applied.


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