fuel delivery concern (starvation)

[Bandone]

this is kinda long but I want to give as much info as possible, 2 years ago I popped a powerhead after 850 hrs , had the boat at a dealer whose name I won't mention for 2 months and they didn't even look at it, finally got pissed and told them look I need an estimate, although I already knew what it needed , I had 3 dead holes. finally john pulled the heads off and said yea you have 3 burnt pistons . He wanted 16000$ for a powerhead, Figured I would look around, found Blackbird motors in PA. complete rebuild was 7200$ in by 9 out by 5 awesome, pulled it from the place I had it and took it to PA, got it done. the dealer I pulled it from was all pissed that I didn't want to pay 16000$ for something I had done for 7200$ , I paid him 350$ for his time to take 2 heads off and say yea it f.......d give me 16000$. I started having fuel problems when I got it back it would just run out of fuel, ball would go soft, have to pump the crap out of it to start would run for about a quarter mild and shut off, time and time again. Now I have replaced everything from the fuel pickup to the motor, new line ,new fuel pump, both electric pumps, etc, still the first thing in the morning it will stall until you pump the shit out of the fuel bulb, then its fine for most of the day, I think you know where I'm going here, I think there's something in the tank thats not suppose to be there, maybe a plastic bag or maybe a shop rag etc. Now before I go down that road has anyone had anything like this, it is a 18 year old tr196, maybe a bad pickup tube , bad screen, ........... any ideas, my next step is to try to get the pickup out and look inside with a boroscope to see inside the tank which you guys know is next to impossible to get to....thanks in advance

[apdriver]

What motor are we talking about?

[javelin90]

I would suggest if you can use a remote plastic fuel tank and hook to motor with primer bulb. Does it have an onboard Yamaha water fuel separating filter? I would try a remote tank first and if the issue resolves itself I would look pull the seat tray and look and see if it has a fuel check valve in the gas tank.

[Lightning 6]

Blackbird Motors…..yikes. Good luck.

[Mechanic Bob]

I would suggest if you can use a remote plastic fuel tank and hook to motor with primer bulb. Does it have an onboard Yamaha water fuel separating filter? I would try a remote tank first and if the issue resolves itself I would look pull the seat tray and look and see if it has a fuel check valve in the gas tank.

^^Agreed to give that a try.
Also, to the OP, did you replace the Anti-Siphon valve? I am NOT suggesting you by-pass it.

[Bass Cat Boats]

Year model of the boat? It could be starving from the pressure valves not venting?

[Bandone]

06 tr196 200 opti....after the fuel bulb eventually get full it runs fine most of the day, 68mph ,,,5700... and blackbird motors had nothing to do with this problem, it was a dealer here in illinois that tied it up for a month and didn't even look at it and was pissed when I pulled it out, haven't pulled the pickup tube out yet, I believe there's something in the tank obstructing the flow, as I said I have replaced everything from the tank to the motor both electric pumps and the primary pump. as soon as I get some time I'm gonna pull the pickup out and take a look, its a bitch to get to, the problem is looking into the tank, after you get that inspection cover off there's hardly any room to get to the fuel line let alone anything else.......had 0 problems for 18 years until 2 years ago

[Dave 620VS]

I had the same problem - the new fuel pump I got was defective - check the parts you have replaced to make sure they are working properly

[Bandone]

shit I hope not it was the first thing I did, but I guess anything is possible now a days, might just buy another one and see what happens....thanks

[Bandone]

ok been doing some homework. If the anti siphon valve is stuck in the "open position" a stuck ball and spring in the valve, will fuel siphon back into the tank, sounds logical to me as this problem just appeared after 18 years of 0 problems.....thoughts?

[Mechanic Bob]

ok been doing some homework. If the anti siphon valve is stuck in the "open position" a stuck ball and spring in the valve, will fuel siphon back into the tank, sounds logical to me as this problem just appeared after 18 years of 0 problems.....thoughts?

What I have found, Failure of the Anti-siphon valve Limits the flow of fuel. It typically does not fail to being open. If there is no AS valve, as in running off a test tank, fuel will not flow back into the tank. (as long as the fuel system is sealed.)
AS valve is to prevent fuel being LEAKED out of a low point failure. AS valve requires a vacuum, negative pressure, to open.

[Bandone]

ok, can it work in reverse to stop flow as in stuck closed or partly closed ? the problem is usually only after first starting in morning or after fishing a long time with the motor trimmed up a little, pumping the bulb feels like pumping air it takes forever to get fuel up to it.....?. This problem just sprang up out of nowhere, never ever had a concern until now ,,,, thanks

[BroWhoop]

One thing, some fuel hoses have liners in them. If they have been disconnected and re-connected the liner can bunch up and restrict flow.

[Mechanic Bob]

I would suggest if you can use a remote plastic fuel tank and hook to motor with primer bulb.

I would do as Javelin90 suggested.

or

FOR TESTING ONLY: I have installed a piece of CLEAR tubing in the fuel line as close to the motor as possible and then looked for "air bubbles" while running the motor.