7.4 MPI no start

[BUIZILLA]

there is a small screen underneath the regulator in the cool fuel rail, take it out, it's a b1tch to get to...................

report your findings

[brwn234]

Is it in a parts diagram or something? Behind where the regulator mounts to the fuel rail. I can't picture it sorry


https://www.mercruiserparts.com/Show...sp?dnbr=809994 98&ivar=images/COMMON/20147.png&inbr=2705&bnbr=110&bdesc=FUEL+PUMP+AND+F UEL+COOLER

Number 16?

[BUIZILLA]

http://www.mercruiserparts.com/Show_...ND+FUEL+COOLER

16 would be it... it's down in the rail about 1/2" or so, pick it out with a pick or needle, if it's plugged or restricted that's your problem

[brwn234]

Well, I destroyed it getting it out because it was pressed in there so tight. I can't figure out which way it flows to know what side the blockage would be on. There really wasn't much of anything. The bottom side(the side I could see when I removed it appeared to have some very very light sediment on it. But nothing that I would think would be of concern. I guess I order another screen now.

[BUIZILLA]

leave it out...

[brwn234]

I'm pretty sure the fuel flow goes down through that screen so I wouldn't necessarily of had to remove it to see any blockage. oh well. I'm wondering if the regulator is bad and not opening or allowing more fuel with engine vacuum. Or maybe its as simple as a vacuum line. I checked those first but maybe I over looked something.

[BUIZILLA]

your problem is unstable and elevated pressure, ANYTHING causing even a slight restriction downwind of the regulator can cause that... it doesn't take much....

not sure why it's even there in the first place, since the return fuel goes back to the fuel filter anyways, which if it hasn't been changed in awhile can cause the same thing

I, and a LOT of others over the years, pretty astute mechanics and surveyors alike, have found that screen to either be a single source or contributing source. If it doesn't solve the immediate issue, then chalk that item off the list

there is another regulator on the port side rear of the main fuel rail, it ties in with the vacuum signal with the lower regulator as well, all good things to check

[TXDONZI]

your problem is unstable and elevated pressure, ANYTHING causing even a slight restriction downwind of the regulator can cause that... it doesn't take much....

not sure why it's even there in the first place, since the return fuel goes back to the fuel filter anyways, which if it hasn't been changed in awhile can cause the same thing

I, and a LOT of others over the years, pretty astute mechanics and surveyors alike, have found that screen to either be a single source or contributing source. If it doesn't solve the immediate issue, then chalk that item off the list

there is another regulator on the port side rear of the main fuel rail, it ties in with the vacuum signal with the lower regulator as well, all good things to check

How do you get the cover off with the motor mount right in front of it?

[TXDONZI]

I'm pretty sure the fuel flow goes down through that screen so I wouldn't necessarily of had to remove it to see any blockage. oh well. I'm wondering if the regulator is bad and not opening or allowing more fuel with engine vacuum. Or maybe its as simple as a vacuum line. I checked those first but maybe I over looked something.

What was the outcome...did you get your issue resolved?

[txtaz]

How do you get the cover off with the motor mount right in front of it?

I just did mine. I replaced the pump and regulator just because they were 16 years old and I was working on the motor at the time. I don't want to touch those again for a long time.

Pull the port exhaust manifold. You need to remove the intake plenum and disconnect the fuel line so you have slack. Remove the two water cooling lines to the cool fuel. Remove two bolts holding the cool fuel to the block. Pull the assembly forward to remove.

You can get an airtex fuel pump (~$100) which is the same as the mercruiser.

[TXDONZI]

I just did mine. I replaced the pump and regulator just because they were 16 years old and I was working on the motor at the time. I don't want to touch those again for a long time.

Pull the port exhaust manifold. You need to remove the intake plenum and disconnect the fuel line so you have slack. Remove the two water cooling lines to the cool fuel. Remove two bolts holding the cool fuel to the block. Pull the assembly forward to remove.

You can get an airtex fuel pump (~$100) which is the same as the mercruiser.

Thank you for the details....I think. LOL

This sounds like a real pain like mentioned above. I was thinking of just pulling the mount and stringer bracket since that would only be 6 bolts......