Fuel starvation 2003 F115TLRB

[captbilly]

I'm having a problem that is driving me nut's. Motor starts & runs great for 25 to 40 miles then I shut it down and fish an area, after 30 minutes to 1 hour I start motor and power up to a plane then engine falls flat on it's face and runs roughly. I turn motor off and pump up the ball (which is soft) then fire up engine and most times it will run just fine or I have to go through the same ritual again or a third time. It will then run as normal for as long as I want until I shut it down again. It will happen 2 to 4 times a day. I have cleaned the VST tank assembly (which had very minor dirt in it), drained fuel tank & visually inspected inside (very clean, had a few flecks of pepper and no water in tank), replaced complete fuel line, replaced fuel/water filter assy, replaced primer ball, performed fuel pressure test @ fuel injector rail results: 42 psi @ idle and 38 psi from 2000 rpm to 5000 rpm. I'm at a loss as to the problem, please help!!!!

[99yam40]

What are the pressures when it will not run properly.
need to test when problem is showing up to see

[captbilly]

fuel starvation F115TLRB

that's the problem doing pressure tests with an intermitant problem that only shows up after a long run while at work. Is there a chance problem could be the low pressure fuel pump. I had ruled that out before in that it is a mechanical pump so it should work or not work and not be intermitant.

[JONSNELL]

I have the same issue with my 2002 F115 and have done all the same as you have.

My issue seems to also be ambient temperature related. The issue seems only to happen later in the day and on warmer days.

Like you said the only thing I haven't looked at is the low pressure fuel pump. This part is not overly expensive so it maybe worth considering.

I have read that the earlier models like ours did have heat issues and there was some sort of "kit" available ( albeit expensive ) but have not been able to get any specifics on it.

Another issue I have thought of is my boat ( Hewes RF18 ) has an anti-siphon valve and these are a known cause of fuel starvation.