Problem starting B&S engine on a craftsman mower

[keakar]

Thanks for your comments.

The fuel line had a filter in it, but I've supposed that a partially plugged filter might impair fuel flow, and in any case the fuel line was old. so I replaced it.

I then inspected the fuel tank, which I found to be contaminated with crud. I removed the fuel tank and repeatedly added gas to the tank and shook the fuel around to entrain the crud and empty it out until the fuel ran clear.

I tried to clean the new carb, which was a $14 knock off. When I took the fuel bowl off, I noted a couple of areas which were ALREADY corroded through the plating on the bowl. Furthermore, the gasket to seal the bowl to the carb body wouldn't fit once it was removed, having stretched and being notably too large to get it back to fit.

At least now I'm satisfied that I have good fuel to the end of the fuel line.

I guess I'm going to buy a B&S carb and try again.

I've assumed that since the mower will start when it has fuel dumped into the carb that the spark plug and spark must be OK. Is that wrong?

It starts reliably when fuel is dumped into the carb, but after 15 seconds or so that fuel is consumed and the engine stops. Even if I manually open the throttle on the carb, the engine still quits. I've presumed that has been happening because of no fuel.

B&S
12F 802-2021-E1
Code 99062966

Briggs and Stratton carburetor part number 799868

have you watched the fuel solenoid function with the key before reassembling it? if its not puilling itself down when the key is on no gas will be sucked up through the carb

you can take it off and make sure its working correctly without removing the carb, just be sure to shut off the fuel supply first

most fit 1/2" wrench size but some of the newer carbs use a metric size im guessing is 12mm

 

[seattlepioneer]

<<
have you watched the fuel solenoid function with the key before reassembling it? if its not puilling itself down when the key is on no gas will be sucked up through the carb

you can take it off and make sure its working correctly without removing the carb, just be sure to shut off the fuel supply first >>

Sorry, I'm not understanding this advice at all.

This mower has a B&S Magnum type engine using a gravity fed fuel supply from the fuel tank to the carb. No solenoid. No key either. (carb part #799868)

I'm guessing that you are referring to a more complex engine with this advice than is the case.

 

[keakar]

I'm guessing that you are referring to a more complex engine with this advice than is the case.

ya, i was thinking you had a riding mower

problem still sounds like restricted or insufficient fuel supply anytime it requires choke to stay running

if you can confirm a good gas stream coming from tank to carb, then trash got in the new carb or its defective and needs replacing

 

[Telesis]

I would take a moment to pull the flywheel cover and make sure the autochoke components are there and working properly (air vane, thermostat, return spring). I just had a unit like yours in my shop and it had a thick mouse nest under the cover causing the engine to remain in full choke all the time. Without the nest, it ran like a top. [Taryl has a nice YouTube vid on the autochoke system if you aren't familiar with it]

 

[Scrubcadet10]

I would take a moment to pull the flywheel cover and make sure the autochoke components are there and working properly (air vane, thermostat, return spring). I just had a unit like yours in my shop and it had a thick mouse nest under the cover causing the engine to remain in full choke all the time. Without the nest, it ran like a top. [Taryl has a nice YouTube vid on the autochoke system if you aren't familiar with it]