Muffler for a K241 Engine

I am the second owner of a 1994 425 AWS with 690 hours that over the last week has developed occasional symptoms of lack of fuel. Initially it was a brief hesitation, but then subsequent episodes became worse to the point it would probably die, but by using the choke I can keep it running until it straightens out. Then after a while it repeats.
I have changed the fuel filter. I looked at the carburetor float yesterday, but it seemed OK, so I put it back together. It ran OK for a half-hour or so then began acting up again. Has anyone had these symptoms? Any guidance? I’m thinking perhaps the fuel pump is intermittently acting up, but thought I’d see what others might say.
Bruce

Bruce it sound's like the fuel tank vent may be plugged up and after it run's awhile is creating enough vacuum in the tank to restrict fuel flow. To get at the vent you need to remove the rear fender's or as many have done including myself get the vented cap used on the later model's. BILL

Bill,
Good thought on the plugged vent. However, when I looked, I found I have a vented fuel cap. I mowed some today and it stumbled a couple of times but also ran fine for quite a while. Guess I'll try checking all the electrical connections next.
Bruce

Keying off the choke symptom you mention I would have thought it would be a fuel flow issue too. Fortunately, there's not a lot between tank and carburetor. Does this same problem occur when not running at full throttle?