Carb Problem, Maybe?

If you have to choke it to keep it running you are not getting enough gas in.

Your fuel tank cap could be the problem if it isn't venting . Run it til it quits again, then loosen your gas cap and listen for the sound of air rushing into the tank, could be as simple as replacing the cap.   

Odds are high its the carburetor inlet adapter screen. I've seen them plug up with varnish to the point they could only let a tractor idle one minute every 15 minutes and wouldn't pass 60 psi air (all the pressure that was in my portable tank that day).

Odds are highly probably that the fuel line itself is filled with varnish. I've seen that too.

Next lower in odds are the sediment bowl screen, and then the screen in the tank inlet, but you say that flows well.

I think there is a drain plug on the float bowl of the carburetor. You need to fix things until that flows a good stream for ten minutes, no slowing or dribbling.

Gerald J.

I've seen machines as stated above that will only run for a minute and shut down, simply because the gas cap vent was plugged or the hole in the bottom of the tank is full of rust. bdallman, has a great idea for checking for leaks (I used either & listened for the engine to speed up, his way is probly safer) . also there was a post on using a dollar bill to check the valves (even though they were just redone). might want to give that a try, simple test and don't cost anything. 

Edited by dt1050 - 05 Sep 2012 at 5:27am

+1 for either vent cap, or fuel delivery.  As Gerald says, that inlet screen... it's IN the fitting where the fuel line enters the carbeurator, and they're frequently missed when doing a basic carb-job, because they're between the fitting and the carb body... people rarely realize they're there.  If it doesn't respond to pulling off the cap of the fuel tank, pull out that screen for a look, I'll bet you'll find it's full of Gerald's Patented Tractor Tank Gak...

This engine doesn't run long enough for it to be the gas tank cap unless the tank is filled really full. Go for that screen or the varnish in the fuel line to the carburetor.

That is not to say that there is ONLY one problem. There could be varnish in that hidden screen, junk in the float valve, float stuck holding the float needle nearly closed, varnish mostly closing off the fuel line, a plugged sediment bowl screen, and a plugged tank inlet screen each adding their bit or lot of impediment to fuel flow.

Gerald J.