GX120 is killing me!

[BLES]

I usually enjoy working on these little Hondas as they usually respond well to simple fixes. This one is killing me, though.

Neighbor's pump. Honda GX120. Ran fine 3 or 4 months ago at last use. Today, starts first pull and runs about 10 seconds then quits. Has spark, and fuel in bowl.

Drain tank and fresh fuel. No change. Clean carb (ultrasonic) even though it appeared clean. No change.

Replace plug. No change. Swap ignition coil with another. No change.

Still starts and runs fine for about 10 seconds and quits with fuel in bowl, and spark.

Suggestions please before I lose my mind!!

BLES

[bgsengine]

Low Oil Shutdown?

[BLES]

No oil alert on this one. Checked that too but forgot to mention.
BLES

[bgsengine]

Check valve clearances? exhaust restriction? Sure the gaskets were assembled correctly after carb cleaning? will it keep running if you give it a shot of gas or carb cleaner down air intake as it starts to die? - Ultrasonic cleaner is not a foolproof fix - can be stuff that just won't come out - maybe swap out the carb with that one you borrowed the coil from.. or try a new carb?

[HondaG100]

No easy way to check but could your compression relief be flaky? Have you done a compression check?

[BLES]

Sorry. Here's the update. It kept appearing to be a fuel problem. Dumped the second tank of new "fresh" premium fuel and dumped some month-old regular from another jug in. Ran fine. 2 out of 3 sources bad! Where to buy fuel now? At least it's working again.
BLES

[38racing]

could the fuel dumping have dislodged something that was blocking fuel flow ?