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Carb bushing(not) Project


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My 10 HP Briggs had a problem. Most of you with that engine have the same problem, or, used to have it? My engine ran fine, made the tractor cut grass, pull a trailer, pull a few small trees, but would not idle at all. About 1/4 throttle and it was fine, any slower was accidental, and then it simply died. We know what causes the problem, and hope someone eventually comes up with a fix. Well. I had wiring to the points problems a couple weeks ago, and decided to also tackle the carburetor problem. 

I have been saving thin pieces of shim stock, thinking I could wrap a piece around the shaft and make the problem go away. .001 shim stock is hard to work with, but was too thick, anyway. So, I got inventive. A spent .22 shell is a tight fit over the shaft, and even that is too thick, so, drag out the files. I almost made it, but wore through the shell in a couple places before it was thin enough. So, that was out. What I did. I loosened the corroded tight thimble on the shaft at the governor linkage end so that it would slip on the shaft easily, then found a spring in my handy spring assortment. The spring was stretched over the thimble, and gives enough tension to keep the new felt tight against the carb body, while still allowing easy movement of the shaft. Another felt on the other end had to be thinner, so a hammer was the tool to thin the felt. I slipped the idle crank  back on, and with a little pressure, was able to put the roll pin back in.

What happened? If any of you have adjusted 2 cycle carburetors, you know they are finicky, and most times even 1/8 turn is too much. My Briggs carb is now that sensitive. I tried several times to adjust before turning the screw back in than back out the 1 1/2 turns, start the engine, and move the screw just a hair, until I finally found the sweet spot. Before the work, I could turn the screw a couple turns each way and not make a whole lot of difference. I oiled the felts, cut the yard, and put the tractor up, allowing it to IDLE before killing it with the switch. Before the work, I parked it and simply pushed the throttle to idle, and the engine died.

I have attached a few pics of what I did. The felt pieces are cabinet door felt bumpers with a 3/16 hole punched in the center. The handy dandy spring assortment paid for itself on one job, and I still have a bunch of springs. I won the assortment as a door prize at an engine show, never thought I would need it, and it has been taking up storage space for about 3 years.






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