B&S 31P777 0299 E1 041118ZE

[Mek-a-nik]

It's on a Craftsman tractor. Customers machine. It's been maintained well, has some hours on it, he has a large property. (He has 2 tractors to have a back up.)
Last year, it began to have a no-start when hot problem. He says run it for an hour, it has to sit a half hour before it will restart. I'm mobile, so I've never seen it do it to check for spark when it happens. I haven't been able to duplicate his problem.
I have:
-Replaced the spark plug.
-Replaced the mag.
-Checked valve adjustment. (To see if they're too tight, hanging open when hot.)
I'm thinking of checking valve clearance when it's hot, to see if they're partially open.
Other than that, I'm wondering if it has a hot soak problem. Like on a carbureted car, the gas boils over in the carb when it's hot, flooding it. (If the float is too high.)
It's a gravity system, I don't think vapor lock is at play here. Maybe I should replace the fuel line and filter, and check the tank for debris, just in case.

[bgsengine]

It's a gravity system, I don't think vapor lock is at play here. Maybe I should replace the fuel line and filter, and check the tank for debris, just in case.

Excellent idea.

Just had one in 2 days ago with the same exact problem - bits of debris in fuel line restricted fuel flow - pull a fuel line off and see how fast it can fill a quart bottle.

[StarTech]

Could it be a heat sensitive fuel shut off solenoid?

[Mek-a-nik]

I'm going to try both ideas. Thanks guys. It might be a while, but I'll update.

[38racing]

I have one with a bad ignition switch that intermittingly cuts voltage to the anti fire.