Cub Stalling

Mon May 24, 2004 8:58 pm

56 lowboy starts right up but immediatly dies. Cleaned out entire fuel system. Still doing it. Thought that maybe air was leaking between carb and intake (stripped bolt, not drawing up tight), fixed that. Still doing it. I can choke it and keep it running, even running smoothly, but with now power. It can't take running in gear and PTO under load. Help...grass is getting high!

Mon May 24, 2004 9:13 pm

You said you cleaned the entire fuel system. Did that include the main jet in the carb?? It sounds to me that the jet may be obstructed.

Mon May 24, 2004 9:45 pm

I took off the carb cover, made sure the needle valve was working, but didn't specifically clean out the main jet. Will compressed air do it well?

Mon May 24, 2004 10:15 pm

If you have an IH carb the main jet is a brass 3/8" hex head. It has a small hole ~.034" at the end and a larger hole on the side. I use a small piece of wire to clear the small hole and then blow with compressed air. I have reservations about using compressed air to blow any air passages as the air may try to force a larger piece of debris through a passage of smaller size.

Tue May 25, 2004 6:45 am

I dont use compressed air at all. I have good results with a wire as Donny said on the stubborn debris and with the aid of a can of carb-cleaner. I use the Wal-Mart (Super-Tech) brand and the air pressure from the straw/tube on the can nozzle has always been efficient for me.

Tue May 25, 2004 8:58 am

Hi Guys, Thanks for the info. Cleaned out the rest of the ENTIRE fuel system. Although I found nothing in the jet, she fired right up. Thanks! Jim

Tue May 25, 2004 9:12 am

jimeyster wrote:Hi Guys, Thanks for the info. Cleaned out the rest of the ENTIRE fuel system. Although I found nothing in the jet, she fired right up. Thanks! Jim


:P Glad to hear of your success story. A lot of times you will not see the trash that you cleaned out as it can be small and still affect the performance.

Tue May 25, 2004 1:46 pm

Fuel doesn't flow thru the carburetor very fast unless you have a major leak. Think of the debris in the carb as acting like leaves blowing around a chain link fence. The little chunks of gunk may temporarily block the openings and drop aside when the flow stops. Some of the more robust particles may actually enter the oriface, but the force is not great enough to really jam it in there unless corrosion is building up in there around the particles.