Fuel pump losing pulse?

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Sorry if cross-posting isn't allowed; I posted this in the Kawasaki forum but it occurred to me that this might not be motor, but mower related. Anyway, feel free to take this down if I'm rule-breaking. :)

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.
 

Scrubcadet10

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when it runs dry, take the line off at the pump where it sucks the fuel up, see if you can feel a pulse.
 

Fish

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Does the engine run fine?
Or does the filter look like it is empty?
Clear filters are nothing but trouble.
 
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Does the engine run fine?

Yes, until it dies from fuel starvation anyway! :LOL:

Or does the filter look like it is empty?

Yes, when the motor dies, the filter is empty. I can re-start the motor and it will run very briefly at low RPM. Throttling up or even moving (anything that causes more fuel use) will kill the motor again.

Clear filters are nothing but trouble.

I bought the OEM Hustler filter, which was clear. I asked what was on the Kohler motors and they showed me a similar (slightly larger) clear filter.

Surely there are some quality filters made from clear plastic?
 

Scrubcadet10

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I bought the OEM Hustler filter, which was clear. I asked what was on the Kohler motors and they showed me a similar (slightly larger) clear filter.

Surely there are some quality filters made from clear plastic?
OEM, ( hustler, kohler, briggs, kawasaki, etc.) are all fine.
 
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Sorry, i meant to say where the pulse line hooks to the pump.

I was afraid of that; That line is nearly impossible to get to on this motor. The bracket to which the fuel pump is mounted is bolted directly above the port. The line from the manifold to the pump is only about 2" long and makes an "S" shape.

I might try to tie a "T" into it though... or temporarily mount the pump elsewhere so the line could be slightly longer. (Long enough to get it off when it dies)

I'll try that, though. Tired of futzing with it tonight. Thanks for the ideas.
 

Scrubcadet10

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I was afraid of that; That line is nearly impossible to get to on this motor. The bracket to which the fuel pump is mounted is bolted directly above the port. The line from the manifold to the pump is only about 2" long and makes an "S" shape.

I might try to tie a "T" into it though... or temporarily mount the pump elsewhere so the line could be slightly longer. (Long enough to get it off when it dies)

I'll try that, though. Tired of futzing with it tonight. Thanks for the ideas.
My mule uses a pump setup like that, and basically uses fuel line for the hose.
 
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