Mower immediately dies

[Tree-Farmer]

I have a Craftsman YT3000 mower, it’s been fairly dependable.

Now it starts, runs for a second, then shuts off. I describe it that way, because it's actually starting, runs, fires a few times.. This is not the standard problem that a mower won’t start. It does start, but immediately dies. When this first started happening, it would run for 10 seconds or 30 seconds before dying, so I was able to drive it back to the shed.

What do you think this could be? What could I check?

I thought maybe the auto shutoff was shutting off gas. I took it out, put 12V on it and the mechanism moves, so that’s working.
But I guess it could still be that, maybe it’s not getting the 12 volts. I tried to measure it, I think it’s getting the 12 V, but only when you start it, so that’s hard to measure.

I don’t think it’s the seat switch, because it wouldn’t start at all, if that was bad, right?

I took out the spark plug, checked it, it is sparking.

I put in a new fuel filter, but that didn't make any difference.

I even tried it without the gas cap, but same thing.

When I remove the fuel line, gas does run out. But I haven’t taken off the carburetor yet.

What do you think could cause the motor to immediately turn off?

 

[Bill_Deering]

You need a constant 12v on the solenoid to keep running. If you measure there when the key switch is in the run position you should have 12v. If not I would trace back to any interlocks and to the key switch. Might be the switch. Also if battery hasn't been charged it might not have enough voltage to keep the solenoid open. Which might point to a charging issue.

 

[NormanSavesTractors]

Did this just start happening?

I would also suggest checking that fuel filter. It looks like you have the craftsman model that is gravity fed, and that fuel filter may be preventing proper flow to the carburetor.

I suggest systematically going through it beginning with easiest solution to hardest:

1. Fuel Filter, Fuel Tank check for clogs, Air Filter. If you do have a gravity fed set up, remove that fuel filter and replace with the ones that look like a toy top.
2. Fuel Solenoid, just remove it from bowl and test with a 12v source
3. Valve Clearances (Common issue)

Good luck,