Small Engines (Lawn Mowers, etc.): Tecumseh 8.0 hp Snow King Carb issues, bolt torque, head bolt

Question
Eric,

Like one of the other people that wrote in I have a snow blower that was given to my by my father. This snow blower has been running really rough for a few years now. Adjusting the screw at the bottom of the float bowl helped a bit last year but I still had to run the engine on almost full choke at all times to keep it running. The engine runs smooth for about 2 seconds and then stubles for 2 seconds. It goes up and down like that with a back fire from the exhaust from time to time. Because of this roughness when I lower to throttle down to half way it will stall some times.  

I just took out the blower today to see if I could get it to run better. I removed the adjustment screw from the bowl. It had some build up on it so I cleaned that off with some fine sand paper. Next I removed the bowl to make sure that the float was not getting hung up. I put it all back together and started it up. I got it running again but still the same symptoms as before.

Do you have any ideas? It sounds like it is starved for fuel and then it gets replentished over and over again. So maybe I have to look closer at the float?

Glenn

Answer
Floats rarely cause this problem unless they have a hole in them.  Usually you can shake the float next to your ear and hear if any liquid is inside the float.  You can also feel the wieght of the float if it is full or you can submerse the float in water and see bubbles come out if there is a hole.

The main cause of surging is the carburetor.  You mention the high speed nut had some build-up on it.  You can bet this stuff has found it's way into every little carb orfice there is.  Normally removing, dis-assebling and cleaning the carb with compressed air and carb cleaner will fix the problem.  For more stubborn carb deposits you can soak the carb in some solution and increase the air compressor to about 60 psi to clean out the carb orfices.

On Tecumseh engines I always check the head bolt torque, 200 inch pounds, and the carb/intake screws for tightness.  I have had several Tecmuseh engine vibrate head bolts loose and cause very poor running.

To wrap it up I would recommned cleaning the carb very throughly and check bolts for tightness.

Let me know what you find.
Eric