Tecumseh HS40 Carb help, only runs on choke

[MAGICMARC007]

Hi fellow OldMiniBikes members. I need help with a tecumseh hs40 engine. It starts first pull and runs great but only with the choke fully engaged. Even after warmup it sputters and dies after I take the choke off. I am guessing the main jet is partially clogged. Any insight into the problem would be greatly appreciated. Thank You.

 

[chrisr]

Looks like you have an adjustable main jet and idle mixture screw on your carb. If you seat the adjustable main jet screw on the fuel bowl (gently) and count the turns you can then take it off and remove the screw and clean out the jet and reassemble with the same amount of turns out like before you started.

If it runs good, great, if not you can try to back off the screw a little at a time which usually the jet screw is more for high speed but if restricted or not adjusted correctly it can be to lean as well as rich if backed off to much.

Hope that helps

 

[manchester1]

Common problem. The emulsion tube is probably clogged. Take the carb off and and give it a shake, holding the float, and see if you here the little ball rattling in the emulsion tube.

 

[massacre]

I just has a similar issue and it ended up being the float height set too low