Fuel pump losing pulse?

[TheRiflesSpiral]

I'm helping my father-in-law with a Hustler Super Mini Z (927277) with a 25HP Kawasaki carbureted motor. (FH721V-CS16-R)

From cold, the mower runs perfectly until it warms up. As soon as it warms up (about 10 minutes of full-throttle mowing with a bagger, not full speed) the fuel filter runs dry.

I assumed the pump was bad and there were some cracked lines so I replaced everything from the tanks to the carb. (Fuel lines, filter, pump, pulse line... not the 2-way valve) No improvement at all.

I considered the pick up tubes might be clogged but it behaves the same way with either tank, and letting the mower sit for 20 minutes or so, the filter re-fills from gravity alone.

The only thing I can come up with is the pulse line losing pulses.

I'm completely at a loss. The fuel system (cold motor, running on the fuel in the bowl) will fill a 1-gallon gas tank in about a minute. Once the motor warms up, there's no flow (outside gravity) to be found.

 

[Convert]

Just taking a WAG . Try running the motor with the gas cap open/off (if that's possible) and see if the problem stays or disappears.
Might not have any venting into the tank, (bad gas cap)
Tom B

 

[bertsmobile1]

GEt a bit of tube and bypass the t-way valve
Could be crud stuck there .
Debris builds up inside the tank and becomes transparent.
IT also partially floats as the grass clippings end up being only marginally heavier than the fuel.
When the mower is running hard & fuel is being drawn down the fuel lines , the debris builds up around the outlet forming a partial plug , much like hair in a shower.
IF you can try a temporary tank and when the engine cut out, hook up the temporary tank
Problem goes away then it is drain the tanks and blow them out from the fuel tap backwards/