8hp brigs & Stratton generator starts but won't stay running

[jigfeett]

Generac 4k generator, over 20 years old
starts but will die unless I hold a hand by air filter to almost choke it
I cleaned out carb and installed new spark plug and cleaned foam air filter plus new gas filter
Oil level is correct so low oil shutdown is not the issue
Any thoughts on what to look at
Thanks

 

[grcauto]

Old fuel?

 

[billr]

Float level, plugged carb needles, plugged carb orifices, plugged fuel line, water in float-bowl... there are many possibilities. The carb probably has to come apart for inspection/cleaning, but try new fuel first; and make sure fuel is flowing freely down to the carb.

 

[jigfeett]

Thanks, I forgot to mention fresh fuel. I never leave fuel in any machine. I did take carb off to clean but
I'll take the carb off again and blow it out. fuel is flowing from tank but I read something about cap vent, I'll look there.
Thanks

 

[dabunk]

It is running to lean your hand acting like a choke to richen mix. Carb is culprit internally

 

[grcauto]

Thanks, I forgot to mention fresh fuel. I never leave fuel in any machine. I did take carb off to clean but
I'll take the carb off again and blow it out. fuel is flowing from tank but I read something about cap vent, I'll look there.
Thanks

Normally these will not starve the engine for fuel until it's run for a minute or two. As the fuel level drops it creates a vacuum in the tank which stops flow. This don't happen right away. Just loosen the cap and it'll vent.

 

[billr]

I suppose I should stress/clarify: "blowing it out" is of little use unless the carb is disassembled so that the itty-bitty passages can be "blown", in both directions. Also, you can inspect visually for crud/damage/corrosion while it is apart

 

[grcauto]

You may want to buy a new carb. They sell them so cheap it's a easy fix.

 

[jigfeett]

Thanks, I'll give it a try

 

[jigfeett]

I opened the cap on the tank and it started right up and stays running .
Still not perfect but good enough for now.
Thanks

 

[billr]

Humor me: the next time you run it, try with the cap back on tight. Let's see if the problem comes back or something else has magically healed itself. I can't believe just a few seconds of running would pull enough vacuum in the tank to stop fuel, no matter how bad the cap is. That's all it was, just a few seconds before you had to "choke" it to keep it running?

 

[jigfeett]

I probably won't get out there for a while but will try, I'm sure there is more issues.
Thanks

 

[grcauto]

I'm curious as well. Unless the tank was filled to the brim with fuel it should run for a minute or two before starving for fuel due to a restricted cap vent.