portable generator

Some background, we have an ice storm coming and I'm trying to fix my parents generator. My father brought it to me because it wouldn't start. I found the carb was horribly dirty and ended up replacing it. I sent it back and then he calls to tell me the grommet in the bottom of the tank is loose and all the gas has drained out. So it came back and I fixed that and put on new shutoff valve, hoses and filter. But in testing now I can't get the generator to run reliably. Sometimes it's fine and will run a load for over 20 minutes and I shut it off. Other times it will start but then quickly shut down. Giving it choke doesn't help when it's dying and it sounds just like the switch has been turned off so I'm pretty sure it's not fuel. I don't see any problems with the ground wire and switch.

It's a 10hp Briggs model 205412 with low oil protection and a tiny screw in dip stick that goes in the oil fill hole on the side/bottom of the engine--oil level reads full. It states in the generator manual that it will not stop the engine if it's running only prevent it from restarting. I do not believe this is a pressure system as I think this is splash lubed. There is one wire from a terminal on top the low oil switch that runs to a small silver box about 1" cubed. bolted right behind the on off switch. That box then has another wire that runs to the on off switch. The on off switch has another wire going to ground and another to the mag. How does this system work? How can it be defeated to test if it's the problem?

For testing, disconnect wire from "small silver box" to "on off switch".

Maybe there is some junk floating around it the fuel tank that sometimes restricts the flow.

I agree with Bob. But as he said just for testing. It has a splash lube system.

No help with your question but I've had 2 champion generators and both of them had flat tanks on the top and they both corroded on the inside and plugged the line to the carb.

If all else fails, pull the line off the carb and see what kind of fuel flow you get and for how long.

Thanks folks--I did as Bob suggested it kept running so I went to the local parts place and got the sensor and it's running! Now finally perhaps I can work on mine. Mine's getting buttoned up following a quick checkup to start the season. I decided to drop the float bowl and check the carb--it was clean actually--but to get the float bowl on I had to loosen the carb from the intake and slide it out a bit and that tore a gasket and well, onto getting that one buttoned up.

THANK YOU EVERYONE!

Thanks for the feedback, good to hear you got it fixed. And, you did it correctly, troubleshoot first, buy parts last! Good luck with the ice storm.