Generator Will Start, run 10-15 min. Backfire, sputter and quit. HELP

[Erv Metoxen]

I have electric, but lent my 4000 watt generator to a family member. They are not expecting to get power till monday. Anyway, the generator is a Generac 4000 watt with 7.8 hp Briggs and stratton motor. It started acting up all of a sudden. Starts after cranking for several seconds, runs for 10 to 15 minutes then acts like it is flooding out. The governer starts reving up and down, spits, sputters, sometimes backfires, then quits. Took the bowl off, some small sediment, needle valve pulled off and cleaned, wasn`t plugged or dirty. Reassembled, and it did the same thing.

What else could it be??

:angry::wacko:

 

[Brian Curry]

Check for oil alert sensor .That will sometimes get stuck .Look at the side of the block for a wire unplug and test.. The fuel cap can cause a problem by the vent being blocked off Loosen cap off and try.

 

[David Ponder]

I agree with Brian. I also have a Generac 5500 watt / 10 HP, and if you dont open the vent on the cap, It will sputter and surge like its running out of gas... (Which it is actually) It happened to me before, but it only ran for about 5 or 6 minutes if I recall correctly. Could still be the vent since the load on it affects the amount of gas it pulls from the tank. (Less load, runs longer before it stops...) Let us know what you find please. Dave

 

[Alan Peters]

You can try the coke plate. That's what the problem was with our Guardian. Its would start, sound like its not getting enough air and die. Readjusted the coke and runs get now. Other than that I think Brian is on to something.

 

[Todd Z]

My briggs did that, It was a dip in the fuel hose, caused a high spot and the fuel wasn't being pushed properly from the tank by gravity into the carb....



I found by shortening the line and keeping it above 1/2 tank keeps it running..



Todd Z

 

[Gavin Allan]

I agree with Big Al and brian.



Sounds like a fuel/air mixture problem.



Fuel tank vent clogged?

Choke not opening?

Air filter plugged?

Clogged fuel line?

Old gas? (if more than a month old, dump it all out and fill with fresh fuel.)

Clogged inlet needle valve in carburetor?

Clogged main jet?

Low float level?