# Throttle decrease by itself



## Dannyrsnowblower (Feb 25, 2020)

Hi there, i have a tecumseh 10.5 hp engine on a 30” snowblower. For some reason, the engine start right up when cold and run well until it get hot a bit. Than, the engine starts to surge and same time, the throttle lower by itself until it stall or shutoff. The governor seem to be adjusted fine. That happens when it’s hot out. (23 fahrenheit and hotter) if it’s -4 fahrenheit and colder, the engine runs perfect. What could be the issu? Thanks for you help and glad to find that forum 🙂


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## Kiss4aFrog (Nov 3, 2013)

:welcome: to SBF Dannyrsnowblower

It would help if you had a way to post or link to a video of it acting up.

Is it an older flat head or a newer overhead valve ?
Does the throttle actually move or are you saying it's surging and the RPM start dropping and then it dies ?
Do you see any blue smoke from the exhaust like it's running too rich ? Choke all the way off ?
Look to see if the choke is physically all the way open when the knob or lever is in the off or open position ?
If it dies on it's own how easy is it to restart ?


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## 2.137269 (Nov 15, 2019)

first off welcome to the snow blower forum. please set up your cp to show where you live "state.country" and what brand & model of machine so we can help you much better . 
as to your problem , when was the carb last cleaned and rebuilt? ? sounds like dirt rattling around in the fuel bowl and being picked up the main jet.. question on my part is the throttle lever loose allowing the linkage to slide all the way done to where it reaches the shut off point?


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## Dannyrsnowblower (Feb 25, 2020)

Thanks guys for the fast respond.

I've edited my profile to show my location.

Here a vidéo showing what's going on. 




That's an old snowblower so i would say flat head ?  It must be close to 20 years old...

It's a mastercraft 31AE5B3H515 10.5 hp tecumseh engine, 30'' wide.

The throttle lever itself move when it happens. I didn't check to see if the throttle itself move but i would think so yeah.

When it dies, the choke is always off. I always start it cold with choke and put choke off when it's warm up and can run fine by itself.

I had the snowblower for 3 years. I never open up the carb to clean it or rebuilt it. Cause i though it was strange that it work no problem when outside temperature is colder.

Those symptom happens only when engine get to a certain temperature.

Tonight, i though that maybe the throttle spring was little weak so i remove the throttle assembly and bent the spring a bit to make it 'stronger' and install it back but that didn't help much. The video was taken after the change...

any idea guys ?

Thanks again for your help,

Danny


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## tabora (Mar 1, 2017)

Surging sounds like a weak throttle spring. See the first video below. You may also need to remove the control bracket that includes the throttle lever and give the pivot rivet a whack or two on an anvil to stiffen up the rotation a bit. 






Here's DonyBoy73's video on the correct linkage configuration for your carb so you can easily get it hooked back up again afterward.


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## arienskids (Jan 26, 2018)

like said above pulling off that bracket, laying it on a flat surface and smacking it with a hammer and punch should take care of the issue


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## Shovel (Mar 26, 2019)

If you wanna be lazy until after the winter.. just wire it up to full throttle

Sent from my LM-Q710.FG using Tapatalk


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## tadawson (Jan 3, 2018)

The fact that he can move the throttle control that far with little to no change in speed is concerning . . Make sure that nothing broke off, and that the gov isn't hanging up. There may well be a friction issue as well, but considering that the OP never bothered to hold the control at full speed so that we could see what happened then doesn't help . . . . and dying at full low is to be expected, since most Tec engines have a shutoff contact that makes at low throttle.


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## Dannyrsnowblower (Feb 25, 2020)

thanks all for your help. it was indeed the fix. after smacking the "rivet" that make it stiffer and fix the current issu. Tadawson, i played abit with the high speed and idle screw. The rpm seem to be more responding with the throttle lever. i posted another video.

i could hear some 'sputtering' especially on low rpm but i wont bother with this little detail 

btw sorry for the blurriness of the video.

thanks all for your help, much appreciated!

Danny


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## JLawrence08648 (Jan 15, 2017)

For the sputtering you are on the edge of a dirty carb. Use some Seafoam, Gumout, in your gas. Take the bowl off and spray some carb cleaner up the main jet then let sit. Many times to eliminate the low speed sputtering you have to remove the side Welch plug.


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