Fuel problem puzzle SOLVED

Bruce Herrington

Bruce Herrington

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Just had both main tanks pumped, cleaned, and topped off with non-ethanol fuel maybe 2 weeks ago; swithed from reserve tanks to the main tanks yesterday.

Running fine for over an hour, throttled up, planed quickly, a mile later the port engine died and never started again, even after replacing spin on filter and the one at the carb. Switching back to reserves made no difference.

Pulled flame arrestor, hit throttle linkage, no fuel getting to carb.

Could fuel pump die that quickly? Didn't find enough trash in either filter to cause this.

It's an old 7.4 Crusader FWC that was running fine on reserve tanks before.

Suggestions?

The push rod that activates the pump refuses to drop; upgrading to electric pump. Thanks again for the quick and helpful suggestions, everyone.
 
When I had a similar problem, it was the fuel pump relay.
 
quote:
Originally posted by Bruce Herrington

Click to expand...


"Could fuel pump die that quickly?"

How quickly is "quickly?" You did not state that you had replaced the pump.

A mechanical or electrical pump can fail instantly. I have had a mechanical pump do just that when I was on the water in a single engine craft.

George
 
May be the oil pressure safety switch. Might just be a bad connection.
 
Disconnect the outlet line on the pump and crank briefly to see if gas is flowing. Then disconnect the inlet side and place your finger over it while someone helps you crank briefly and feel for vacuum. This will rule out a blockage in the lines. If the diaphram failed, make sure you change your oil too.
 
George, no sputtering, just died. Wondered if fuel pumps die quickly or give warning?

Cam , I'll check that, didn't they had a connection.

Stephen, good idea, was hoping there was a test to eliminate something. :-)

Thanks, everyone.
 
...and to eliminate electrical, squirt some gas or carb cleaner in the carb and see if she'll fire.
 
I'd do as Charlie suggests to see confirm it has ignition and will fire with known good gas ( use the blower) .

Was there any fuel in either filter when you changed them? Why were the tanks cleaned? Was the pickup pulled from the tank at any time?

If it does fire but does not retain prime or otherwise shuts off on it's own supply, I would consider the mechanical fuel pump, suction leak at filter seals & fuel line connections , particularly if any of those were disturbed during the cleaning process, *anti-siphon valve*(clogged or broken? - & can have delayed effect on fuel supply), tank pickup tube ( broken , porous or clogged sock?) and clogged tank hull vent.

Does a sample of the existing topped-up fuel smell nice and fresh-gassy and look normal color/clear?
 
Yes, fuel was present at both filters the first time I changed them after it died. But none afterward.. Main tanks hadn't been used in over 2 years. Lot of trash in port tank, starboard in good shape though.
 
Scenario one,
Small amounts of trash from the cleaning process, migrating up the feed lines can collect at any fitting like anti-siphon or Y valve. Any fitting that lets any debris collect will continue collecting debris.

Scenario two,
The fuel pump has relatively low vacuum in the feed side of the fuel pump. Doesn't take much much to stop it up. It also needs good solid fuel line connections or that vacuum side of the fuel supply lines will readily suck air rather than the fuel.

Sounds like one of these fuel supply causes but don't forget to check for fuel in the over-flow line on the pump that would indicate a ruptured diaphram.
 
quote:
Originally posted by Bruce Herrington

George, no sputtering, just died. Wondered if fuel pumps die quickly or give warning?

Cam , I'll check that, didn't they had a connection.

Stephen, good idea, was hoping there was a test to eliminate something. :-)

Thanks, everyone.

Click to expand...


When my mechanical died there was NO warning.

The boat was an IO so changing out pump was very easy job.

George
 
Is there a way to connect a portable tank after the filter and prior to the pump?
 
Did you switch back to the reserve tank to test the fuel pump theory? If it is the anti siphon valve on the main tank then the reserve tank should run the engine. If it is a fuel pump issue, no tank would help.
 
Yes, switched back to reserves after changing filters. Looking more like pump related problem?
 
Bruce,

The subject now shows Fuel problem puzzle SOLVED but there is no new post as to what the resolution was. ?????
 
quote:
Originally posted by New2Me34C

Bruce,

The subject now shows Fuel problem puzzle SOLVED but there is no new post as to what the resolution was. ?????

Click to expand...


Check the last sentence of the edited original post.
 
So i guess the electric fuel pump fixed your problem. But i still have to question the reason the fuel pump to cam pushrod being stuck? Did you leave it out now? did you leave the mechanical pump off?
 
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