stumped in Mississippi

[Fred Pittman]

Hello all...new to the board from Mississippi.
I recently purchased a used (only 37 hrs. run time) 2007 F60tlr for my pontoon boat. The motor sat up for 3 years with old fuel in it and the previous owner tried to start it but couldn't. I got new gas tank, fuel hose with primer bulb, new plugs, new water pump, and new fuel filters. Motor still wouldn't crank. I removed the injectors, cleaned the injector filters, removed the vst assembly and found a bad fuel pump. (appears that it had overheated). The vst was full of old contaminated fuel. I cleaned it thoroughly and installed a new fuel pump that I got off EBAY . (not an OEM pump) I reassembled and it fired right up and ran great on cups in the yard. Off to the lake I go and for the first half hour it ran like a champ, then sputtered and died. I squeezed the primer bulb ( was not collapsed but not rock hard either) and got going again only to have it sputter and die at the boat ramp a few minutes later. I just rented a fuel pressure test gauge from my local auto parts store and attached it to the schrader valve on top of the vst and getting no reading either with key on or with engine running. The motor cranks good and seems to be running fine. I cut engine off and disconnected the gauge and got no fuel leaks when disconnecting the gauge so I depressed the schrader valve and am getting nothing. (no fuel, no pressure hiss)
Should this motor even crank and run without adequate pressure from the hi-pressure pump? I am ready to remove the vst again and replace the pump with an OEM pump if that's necessary but really don't have the extra $$$ for an unnecessary second high pressure pump. It has always been my understanding that injectors have to have adequate fuel pressure to fire. Am I hooking gauge up to the wrong schrader valve? I only see one . I can crank engine and as it's running I can depress the schrader valve and am getting nothing......What gives here? Thanks in advance for your help, Fred

[TownsendsFJR1300]

When you pump up the primer bulb and then it runs, your low pressure fuel pump is likely shot. Its that pump that fills the VST.

Your only getting fuel to the VST when pumping the bulb,(doing the work manually of the LP pump) then it runs out of fuel and stalls. There's literally no fuel for the HP pump in the VST to move...

The diaphragm usually leaks and stops pumping...


Note, if there's an air leak somewhere prior to the fuel pump, that would also cause similar issues..

[Fred Pittman]

Thanks, Scott. I have determined that the Schrader valve on top of the vst has to be clogged. Engine is running and no pressure there. I missed changing the filter between the primary pump and the vst also. I am at work now so I cannot check but tomorrow I will try a valve core tool to see if I can get the Schrader valve cleaned out in order to get a pressure reading and go from there...... Thanks, Fred

[rodbolt17]

does the shrader valve your messing with have internal or external threads?

go ahead and replace the lift pump diaphragm.

old gas eats them.

check your oil, if the diaphragm fails it fills the crankcase with gas.

[Fred Pittman]

OK, I just removed the valve core from the schrader valve and it was clean. Then I took the entire valve out. Not seeing anything gummed up on it either. Turned the hose on, fired the motor up and it's purring like a kitten without the schrader valve on the vst. No signs of fuel anywhere.

[Fred Pittman]

I checked the pulse pump diaphram weeks ago when flushing the old fuel from the engine. It's not leaking, no fuel in the oil.

[99yam40]

Respond to Robolt, he is a Master tech and he will help you

[Fred Pittman]

OK, i've determined that the schrader valve on top of the vst is only a vent to drain the vst box.(thanks Rodbolt, you are correct).
I moved my engine up to the top holes on the transom as on the maiden voyage I had a lot of splash all over the back of the pontoons and over the fuel tank. I noticed that the lower part of the motor bracket where the two anodes are mounted was maybe 1/2 " below the transom lower plate and hopefully this was causing all the splashing. I drained the vst box and got 1 1/4 cups of fuel and about 3 drops of water . I'm thinking that possibly the engine sputtered and died because of water being splashed into the tank vent and picked up and sent thru the fuel system. Going to drain the gas tank today and refill with fresh non-ethanol , flush out hoses and fuel lines, and take her back out on the water for a second trial run. Thanks everyone...,I'll keep you posted, Fred