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jdm

Worn throttle shafts

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jdm
I tried to do my homework before bothering you guys. I searched for posts about throttle shaft wear. I learned alot. I still have questions. Is it possible for an engine to be adjusted to run right when the wear allows the shaft to move a sixteenth inch or more in slop? It seems to me not. It must be sucking alot of air. Where does a guy get parts to fix this? I have several engines where I believe this to be the problem in not running right. Thanks

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HubbardRA
You can check with a local small engine shop, or use one of the site sponsors like Sandy Lake to order the parts. I have fixed a couple Kohler carbs. Have yet to do a B/S. With a worn shaft you will have spitting and sputtering of a random nature when running at idle and low rpms. It is usually not to significant at wide open throttle.

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gtwygreg
I had considerable slop in my throttle shaft on my 16 hp cast iron Briggs. I replaced the throttle shaft and bushings and it did make a huge difference. I was easily able to order the new throttle shaft at Auto Value, but their books or microfiche did not show a part number for the throttle shaft bushings. If I could get a part number the parts guy said I could most likely order them. I was able to find and order them on ebay. The part number is #23108 for this application in case anyone needs it to order replacements. I've attached a picture as well.


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npalen
I fixed the worn throttle shaft on my 720 with an O'ring on the shaft with a light compression spring behind it. This holds the O'ring against the side of the carb to prevent sucking air. Nelson

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DeltaBravo
This is an older topic, but I thought I would post here because of the title. The B&S manual has a lot of good information including how to replace the bushings. It's straight forward but the first time through can be a big help. After removing the throttle shaft and noting the orientation of the parts, thread a 1/4-20 tap into the bushing. The tap is smaller than the bushing. As long as it goes in reasonably straight you won't hit the carb body. The bushing will start to spin anyways. A vise is recommended to hold the tap and this makes it easy to remove the bushing once the tap is threaded into it. Spin and pull on the carb body to spin the bushing out. A drop of penetrating oil on the inner edge might help. Repeat the other side. Clean the bores, lube with a drop of light oil or penetrating oil. To install the bushings, use the vise with cardboard against each jaw to protect the bushing end. You will be able to start the new bushing by hand so it holds well enough to position in the vise with the cardboard. Make sure the carb body will not get squeezed or part make break or crack. Slowly close the vise, drawing in the bushings. Double check the clearance of the carb body in the vise. Close vise jaws until bushings are seated. I suppose the bushings could also be installed with a big pair of channel grips. Just avoid the bushing going in crooked and damaging the carb body.

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jdm
My problems have been with carbs on my Kohlers. Just to see on one of my crappy running tractors I set the throttle at an off idle point, shut it down, and then siliconed around the throttle shaft and let it dry. When started again it purred like a kitten. Guess I know where the problem is now and need to fix it correctly.

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