Cyrax

Tecumseh Engine Revs Too High

I have a Craftsman lawnmower with Tecumseh engine/carb. One day I went to start it after it had gotten wet from rain and the carb gave a loud pop and a little white explosion came out of it and it would no longer run. Fuel just leaked out of the carb. So I disassembled the carb and found a hole in the float. I replaced it with a new one, plus a new seat for the needle, and cleaned it best I could. It now starts up and run steady, but rpm's are way too high. The linkage is all the same as before, and the governor arm moves freely. Did I maybe miss some debris in the carb during cleaning and engine isn't getting enough fuel so runs lean?

There's no throttle control on this mower, it's preset. When I manually throttle it down on the carb, it slows down but seems to run a bit erratic.

Thanks

cheese

Sure sounds like a linkage problem, maybe connected in the wrong hole or a spring binding. When you say it runs erratic, that makes me think it still needs some carb cleaning.

Cyrax

This is my mower:



It's hooked up like this here(not my mower):



Are there any specific ports on the carb that would cause this behavior?

cheese

If it's running too lean it could run a bit higher than normal, but generally it just surges when it's too lean. See the tab where the spring connects? Any way that could have gotten bent? That is where you set the rpm.

Cyrax

Yeah I read about that tab, how you can set the rpm with it, so I tried bending it but it still seemed to run too high, as if something else was off.

cheese

Bend it toward the air filter to slow it down. Does the governor seem to be working? (when you rev it by hand, it should push back to try to slow it down)

Cyrax

Hmm, I will check this. You mean disconnect the linkage and monitor the governor arm while opening the butterfly valve?

cheese

No, don't disconnect the linkage, just rotate the throttle open a little by hand and see if it has much more resistance than when it's not running.