# 10 HP Techumseh Surge, even after new Carb - governor spring?



## Steveo66 (Jan 21, 2018)

Sears Crafsman Model C950-52330-3 , 10P Techchumseh Snow-King

Ok, pulling my hair out on this one. Surge remains even after brand new carb, clean gas etc. Even pulled the bowl and main jet to ensure there was no debris. Adjusting the main jet does not remove the surge I am thinking it is probably the spring on the throttle lever that provides tension for the governor. I have seen other posts pertaining to this issue, and a couple youtube videos as well. This pic below is the spring I am referring to here. I did remove the linkage plate assy and the spring and used a couple pairs of needle nose pliers to "tighten the spring" a bit as I could see it was a bit out of shape compared to that below. However after reinstalling it, things were no better, maybe even a little worse. Installing it is a bit tricky and does require stretching the spring a bit, so perhaps the spring steel is just worn / weakened and just lost the ability to do it's job.










See this video here for exactly what is happening. Watch Video.  The surging is worse at lower RPM and I really can't get it to idle well either, and when I increase to full throttle the surging smooths out quite a bit but is still a bit detectable at at full throttle. If I attempt to hold the lever from moving back and forth, the surging smooths out, which to me is another indication that this is an issue with the spring, and not the carb.

I am about to go ahead and order a new spring.. can anyone confirm / validate that this is likely what the issue is?

Thanks for your input.


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## crazzywolfie (Jun 2, 2014)

does it have and adjustable carb? if so have you adjusted the idle mixture screw?


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## oneboltshort (Dec 16, 2019)

Like crazywolfie mentions, you should be able to get rid of that with the side jet visible in your video. That throttle assembly appears fairly worn out, you can get whole assembly on amazon/ebay cheap. You can try taking yours off the housing and smack the back rivet with a hammer, sometimes it'll get them to crimp together a little better.


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## Steveo66 (Jan 21, 2018)

crazzywolfie said:


> does it have and adjustable carb? if so have you adjusted the idle mixture screw?


Thanks for your response. Yes, I should have mentioned that as well.. tweaking the idle mixture adjustment does not seem to help either.
See this video for what I was referring to when I mentioned others have seen the spring issue.


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## crazzywolfie (Jun 2, 2014)

i don't really see that causing a surge or enough to worry about if that is what your machine is truely doing but i would guess your machine must be worse than that if your asking about it. do you got any video of what your machine is doing?


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## oneboltshort (Dec 16, 2019)

I don't see much help in that video you linked in post #4. The guy fumbles with the spring and didn't know how to set the tension. At the 6:35 mark you can clearly see he simply replaced the carb. The spring didn't fix anything. Not saying yours wouldn't benefit from a spring change, just the video doesn't prove the spring fixed his surge.


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## oneboltshort (Dec 16, 2019)

I just looked back into my bookmarks and the throttle bracket I have bought in the past is listed as no longer available on amazon. It was a ramen noodle special by woxla for like $9 and came with clamps, filter and handles, but no more I guess so disregard my other post about a cheap alternative.


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## Steveo66 (Jan 21, 2018)

crazzywolfie said:


> i don't really see that causing a surge or enough to worry about if that is what your machine is truely doing but i would guess your machine must be worse than that if your asking about it. do you got any video of what your machine is doing?


Yes, there was a link in my original post above. Here it is again (it will not allow me to insert as Media, so just the link again)

Watch Video.


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## Steveo66 (Jan 21, 2018)

oneboltshort said:


> I don't see much help in that video you linked in post #4. The guy fumbles with the spring and didn't know how to set the tension. At the 6:35 mark you can clearly see he simply replaced the carb. The spring didn't fix anything. Not saying yours wouldn't benefit from a spring change, just the video doesn't prove the spring fixed his surge.


Thx for the info. This is not the only reference to this I have seen -- here is another comment below. . after all the messing I have done with the Carb, before and after replacing, I think I have all but ruled that out, as well as vacuum leaks, gasket leaks etc. Here is one of a few other comments I have seen: re this spring.

I have a Craftsman 9HP snowblower and it would surge. I watched some videos online and first tried cleaning out one of the jets and then tried blowing some Berryman B-12 into the carb with no luck. Another video suggested replacing this spring and that did the trick.


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## tadawson (Jan 3, 2018)

Not sure why you would expect the idle needle to fix a mixture issue when you clearly are not at idle . . . Totally clogged idle needle can cause a surge, but also results in an inability to idle at all. Did you clean the tiny idle passages in the brass fitting at the bottom of the float bowl? Or pull the welch plugs to do a complete cleaning? This seems mkre like a mixture issue than a gov issue to me.


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## crazzywolfie (Jun 2, 2014)

tadawson said:


> Not sure why you would expect the idle needle to fix a mixture issue when you clearly are not at idle . . . Totally clogged idle needle can cause a surge, .


i would have hoped he has already played with the adjustable jet since he put a new carb on it. the idle mixture is more likely to get over looked and can cause surging. i would hope the issue is as simple as a mixture issue but hard to say. in his video for about 1 second when he held the throttle all the way up it almost seemed like the surge went away


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## Oneacer (Jan 3, 2011)

I would say the side mixture screw also .....


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## Steveo66 (Jan 21, 2018)

Ok, good info from all, thank you. Let me take another shot at adjusting that side mixture needle.


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## Steveo66 (Jan 21, 2018)

Ok, just an update on this. Thanks again for all the suggestions. So what I did before trying a new spring, was to step back and go back to the original suggested settings and tweak from there which has solved my problem. I started with the static governor adjustment on the governor arm, which helped a little, but I still had the surge at less than wide open. Next, I set the high speed mixture jet (bottom of float bowl) at 1 & 1/2 turns out from closed and for the low speed mixture jet (side jet), I set it to 1 turn out from closed. I started it up again and tweaked the high speed mixture when running at wide open, and next went to the low speed mixture. I ended up opening up the low speed mixture jet about another 2 full turns (3 turns in total from closed) to get a smooth running engine at both idle and interim speeds up to full throttle.

So, I am pleased now, and ready for the next decent snowfall to give it a good test under load. If it falters at all under load, I will plan to further open the main jet, about 1/8 turn at a time. In summary, I think the key here was stepping back to initial settings and having the discipline of adjusting one setting at at a time. It seems a little strange to me that the low speed mixture is at 3 turns out to get it running smooth, when most of the info I have seen suggests 1 to 1-1/2 turns out -- but so be it, I am not complaining .


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## Oneacer (Jan 3, 2011)

The 1 1/2 turns is a general starting point, as well as finding a starting point of one on the side... of course depending on the carb setup, cleaning, imperfections, obstructions, etc, etc,,, getting both mixture screws finely adjusted by ear is what I do.

Sounds like you learned a valuable course of action going forward.


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## tadawson (Jan 3, 2018)

Either your carb is "just like that", or the 3 turn requirement indicates that it still isn't clean in the tiny idle passages. (Typically, I find the latter . . . some of those passages aren't much bigger than a hair . . .)


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## Steveo66 (Jan 21, 2018)

tadawson said:


> Either your carb is "just like that", or the 3 turn requirement indicates that it still isn't clean in the tiny idle passages. (Typically, I find the latter . . . some of those passages aren't much bigger than a hair . . .)


Could be.. it was a new Carb at the beginning of the season, and I do have a fuel filter in the line and it is fresh gas (premium, ethanol free).


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## schneetag (Jan 3, 2021)

tadawson said:


> Either your carb is "just like that", or the 3 turn requirement indicates that it still isn't clean in the tiny idle passages. (Typically, I find the latter . . . some of those passages aren't much bigger than a hair . . .)


There have been a few times where I had to clean them out using a piece of thin guitar string. Otherwise, when cleaning a carb., I'll butt the carb. cleaner straw up against the small openings as best as possible, and spray carb. cleaner into them. I look for the cleaner to spray out of the other small holes. I do this holding everything away from myself, since there is bound to be "overspray".


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## tadawson (Jan 3, 2018)

I do the same, but with a single strand from some copper wire. Harder materials (steel guitar strings?) can damage the brass jets.


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## Steveo66 (Jan 21, 2018)

tadawson said:


> I do the same, but with a single strand from some copper wire. Harder materials (steel guitar strings?) can damage the brass jets.


Yes, I have seen that suggestion before as well, given that copper is a softer material. Also, for what it is worth, my new carb came with a set of these cleaners.


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