I just cleaned out and rebuilt my carburetor on my 3.5 HP Tecumseh and was wondering how to get the perfect idle tuning. It idles rough now and wants to move forward when I start it up and I have two screws with the needles on them. One is on the bottom of the carburetor's bowl and the other screw is on the other side of the choke. How much should I turn both of them to get a stable idle without it stalling and the bike jolting forward?
Tecumseh 3.5 HP carburetor idle tuning
I start out by finger tightening both screws in. The bottom one I turn back out 1 to 1 and 1/2 turns. The side one, I turn out 1 turn. The bike should be up on a stand or milk crate btw, while you're doing this because the next step you need to give it full throttle.. or you could disconnect the chain if you can. For the bottom screw, you need to adjust it while at full throttle. You back the screw in and out until it runs as smooth as possible. Once you get it where you want, you let the throttle go and work on the side screw. AT IDLE now, you back the screw in and out again, until you find the sweet spot and it idles perfectly. Thats all there is to it!!! I have a few video links too, Ill post when I find them!
These should help ya out too:
These should help ya out too: