Starts but won't run

[allenm]

Got a Craftsman lawn mower, Tecumseh engine, that'll start with a squirt of starter fluid but won't run beyond a few second. I can't find the Tecumseh model number but the Craftsman model of 143.434332 gets me to this web page https://www.partstree.com/models/143-434332-craftsman-engine-made-by-tecumseh/

I have:
- replaced the carb
- emptied and cleaned the gas tank
- replaced the spark plug

Also, and I have no idea whether this is related, every now and then when a try to start it I get a clanking sound like the blade's loose. But it isn't.

 

[Rivets]

Craftsman number crosses to a Tecumseh engine model TVS 120 - 63918J.
First, if you purchase the carb from FleaBay or AutoScam I’m will to bet it is bad. Cram shoot when purchasing there. I’m guessing that your original carb is still good, just needs a good cleaning and the replacement of carb float needle and seat, part number 631021B, plus setting the float level properly or slightly rich. I’ve attached a service manual for you engine. https://www.mymowerparts.com/pdf/Te...P-4-CYCLE-L-HEAD-FLAT-HEAD-ENGINES-692509.pdf