# High Rev and Throttle Control



## GotZoom

Hello All,

Well after 22" of snow over Christmas I was up early and ready to plow my driveway. I have a craftsman model 247889571. Everything started out fine, normal carb issue and had to leave choked. My new carb was supposed to be delivered last week but still hasn't arrived. After about 2 hours of plowing, the engine started to rev really high in both choked and run positions. I tried to use the throttle lever to adjust but it did not control any level of speed throughout the range of the lever. It did cut the engine when it moved to stop though but again nothing between the rabbit and the tortoise if you will. 

I have not taken anything apart yet but I can see the lever moving freely and I can also see the cable moving however I cannot tell the range of motion or whether or not it has any tightness or free play. 

Could moisture have traveled along the cable and froze inside the cable tube? I tried it again today I have the same issue. I also noticed that if I leave the choke about half way the engine does not rev high so I let it warm up for a few minutes and also worked the throttle lever back and forth but still wants to overspeed when I move the choke to full or run.

Any thoughts or suggestions would be appreciated.. Thank you!


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## Marty013

sounds like you have air coming in somewheres it shouldnt..


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## drmerdp

I suggest taking a quick look at the throttle linkage and governor arm and spring. If something is obviously bent missing or misaligned then great. There is the potential for a governor gear issue which would be a real problem.

How high is the engine revving? Is it significantly higher then when it was working properly? If so beware of catastrophic engine failure. 3600rpms is the max.


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## UNDERTAKER

*Could be the beginning of a Govenor issue. what brand of engine is it??????????? Anyhoo ALOHA from the paradise city.:smiley-rpg027::smiley-rpg027::smiley-rpg027::smiley-rpg027::smiley-rpg027:*


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## GotZoom

Yes, it is significantly higher than normal operation.. I did shut it down right away both when it first occurred and as I tested it today. Scared the crap out of me and of course you can't do anything fast enough in a case like this.

I will try to take it apart in the next day or two and see if anything looks kinked, bent or damaged. 

Is the governor gear issue worth fixing if that is the cause. I am fairly handy with tools and youtube, but not great at taking apart small engines. Figured it would be easier to replace the carb than to rebuild it and I think it even cost me less.


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## GotZoom

Marty013 said:


> sounds like you have air coming in somewheres it shouldnt..


That could be possible, but I am not sure I can test it with the overspeed as I do not want to kill the engine. The testing procedure I have seen is to spray carb cleaner or wd40 around all of the gasket seals to see if changes the rev. Is their another way without the possibility of further damage?


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## GustoGuy

POWERSHIFT93 said:


> *Could be the beginning of a Govenor issue. what brand of engine is it??????????? Anyhoo ALOHA from the paradise city.:smiley-rpg027::smiley-rpg027::smiley-rpg027::smiley-rpg027::smiley-rpg027:*


 



I agree it sounds like a governor issue or a linkage issue to the governor. If it is an older Flat head Tecumseh you need to fix it right away because the engine is in danger of blowing a connecting rod at rpms over 3600. Governors are essentially designed to slow down the engine if rpms are getting too high. Basically it is a centrifugal speed control were the governor forces the throttle to close if the engine turns at more than 3600 rpms,. Basically it is a small gear and lever assembly inside the engine, which at a certain rpm the lever extends and that movement is fed through a linkage back to the carburetor to close the throttle to prevent over revving of the engine


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## GotZoom

POWERSHIFT93 said:


> *Could be the beginning of a Govenor issue. what brand of engine is it??????????? Anyhoo ALOHA from the paradise city.:smiley-rpg027::smiley-rpg027::smiley-rpg027::smiley-rpg027::smiley-rpg027:*


I honestly do not know the brand, but from what I have seen online and in reference to the model number it is one from China.. The engine part number is 952Z270-SUA which comes back to troy built and mtd


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## UNDERTAKER

2 options you have here, try and fix that 1 or head down to harbor freight and get a new engine 4 it. but I think parts for your engine just might be hard to find. and 4 99.00 bucks you get a shinny brand new engine.


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## GotZoom

POWERSHIFT93 said:


> 2 options you have here, try and fix that 1 or head down to harbor freight and get a new engine 4 it. but I think parts for your engine just might be hard to find. and 4 99.00 bucks you get a shinny brand new engine.


Yep.. I am starting to think new as well.


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## Marty013

leak down test... you should see something abnormal and you be able to use soapy water on gasket areas to check whats leaking.. however.. this wont check if air is coming in from a leaking carb to intake manifold gasket.. nor a block to intake manifold gasket.. so basically only your head gasket would get checked.. and valves.. you would be able to eliminate or condemn those last 3 components... trouble shoot your other 2 potiental gaskets first (brake cleaner or other spray solvents as the engine revs normally... carefull to not get anything in the carbs throat as it could mislead you)


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## merdody1

Watch Donyboy73 youtube instructional video on Throttle adjustments. It really helped me with my tecumseh 9hp adjustments.


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## Bob Cat

I'd first check the throttle plate in the carb to see if it still there


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## skutflut

GotZoom said:


> Hello All,
> 
> 
> 
> 
> Any thoughts or suggestions would be appreciated.. Thank you!


What year is your machine? Looking at that part number at sears.com, shows as an OHV engine on a 24" blower. Assume the engine is chinese. Is it still under warranty?


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## Grant D

GotZoom said:


> Hello All,
> 
> Well after 22" of snow over Christmas I was up early and ready to plow my driveway. I have a craftsman model 247889571. Everything started out fine, normal carb issue and had to leave choked. My new carb was supposed to be delivered last week but still hasn't arrived. After about 2 hours of plowing, the engine started to rev really high in both choked and run positions. I tried to use the throttle lever to adjust but it did not control any level of speed throughout the range of the lever. It did cut the engine when it moved to stop though but again nothing between the rabbit and the tortoise if you will.
> 
> I have not taken anything apart yet but I can see the lever moving freely and I can also see the cable moving however I cannot tell the range of motion or whether or not it has any tightness or free play.
> 
> Could moisture have traveled along the cable and froze inside the cable tube? I tried it again today I have the same issue. I also noticed that if I leave the choke about half way the engine does not rev high so I let it warm up for a few minutes and also worked the throttle lever back and forth but still wants to overspeed when I move the choke to full or run.
> 
> Any thoughts or suggestions would be appreciated.. Thank you!


I have had the same problem once in a while, especially in extreme cold and when blowing deep snow. It turned out the air intake was getting choked with snow / ice. On my Briggs & Stratton, the air intake is on the rear, left (when facing forward). An oblong opening in the bottom of the plastic shroud. Under the carb. 
After removing all the ice and snow I could find on the carberator (to no effect), I started tapping (rapping?) the shroud with the handle of a screwdriver. Snow started sprinkling out of this port. Eventually, quite a bit of snow came out, along with a couple large chunks of ice. At that point I restarted the engine and it idled down to normal. I believe snow was getting sucked into the intake area, either starving the engine of oxygen, forcing the governor to go to max power, or it was preventing soome mechanism from moving normally. The weather was very cold (-30 C), which would keep the engine heat from melting this snow.
Try making sure there's no snow orice built up inside the air intake for the engine. A heated garage (which I don't have) would be ideal.


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## wazzy86

Dealing with the same thing trying to blow out my driveway here in North Dakota. -11f more like -35 with wind chill. My Briggs and Stratton started revving way up and bogging down more than normal when actually blowing snow. This isn't the first time I've dealt with this. Put it in the garage and cranked the heat up to 65. Let it thaw out for a bit and it will be good to go again.


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