Engine is fuel starved at crusing speeds

[snooksniper]

I have a 2001 grady white with a 200 sxtxrx OX 66 engine. Then problem I am having is the primer bulb becomes empty at crusing speeds after a few minutes if that. To operate at fatster speeds i need to squeeze the bulb about 60-70 times permintue to kep a steady fuel flow I have done a fuel pressure test and I have reccorded 38 PSI, the range for my motor is 41-49.
The steps I have taken to resolve the issue are, replace all fuel filters, fuel water seperators and removed the non servicable fuel injector filters. Before Idid the last step listed the boat could not go fast at all. Now it operates somewhat better but still does not run 100 percent. If it helpes 5 of the 6 filters were in poor condtion but one of them looked ok. I have also dissassembled the fuel system and put it back together from the fuel line that goes from the engine to the primer bulb, which has also been replaced, now did i discover any blockages in the line. At this point I feel that one fuel injectors is bad, the vst pump needs to be replaced, or the tank must be cleaned. Any thoughts or help from past experience would greatly be appreciated, i can't stand to see my boat on the lift any longer!!!

 

[gss036]

Re: Engine is fuel starved at crusing speeds

How about rebuilding the fuel pump.

 

[snooksniper]

Re: Engine is fuel starved at crusing speeds

I forgot to write that in my first post, one fuel pump is brand new and the other has been dissambled and inspected and is in working order.

 

[cousinabe]

Re: Engine is fuel starved at crusing speeds

low pressure pumps.

 

[rodbolt]

Re: Engine is fuel starved at crusing speeds

sounds like one of your lift pumps is defective/weak.
by manually pumping the primer your bypassing the lift pumps and filling the VST manually.

 

[snowmon]

Re: Engine is fuel starved at crusing speeds

is the primer filling with fuel and firm? if so could be bad lift pumps but if you've changed out other components you might have an air leak at one of the joints between the bulb and lift pumps. or it could be a supply side problem. if the primer bulb is not filling completely with fuel and collapses check the anti-siphon valve at the hose end of the tank pick-up. if you've recently switched to e10 fuel it creates all kinds of issues with deposits that resemble tiny grains of sand that will keep the anti-siphon valve from working and usually leave it stuck in the closed position.