cool fuel or???

[rcmafgny]

have about 400 hours on my 06. 8.1L B3
This past spring the engine was a little rough especially under load and thought i needed to replace the dreaded cool fuel module. Did fill up boat early in the season with gas from a station that was decimated by hurricane Sandy, so maybe water in the fuel? Treated it, changed the filter. Mechanic said to change the plugs next which i did and the problem seemed to go away for the summer until now.
Now it seems to "miss" under load again.. The miss is Noticeable over 3000 RPM. i also think it idles a little rougher then normal. I did recently get fuel again - and just changes both filters [the disc and the canister in the cool fuel module. the disc filter was gross, the canister looked ok.
The problem seems better but still noticeable. Thoughts on what to do next? do i bite the bullet? Can a mechanic tell from plugging in the engine to a scanner and tell if one injector is bad? could it be wires?

Frustrated... thanks

 

[cjcray]

I have a 1997 370 with 7.4 MPI engines.
my starboard engine this season lost power above 3000 RPMs.
i changed the plug wires per the suggestion of another club Searay member and it solved the issue. I see where you said you changed the plugs. I would suggest changing the plug wires.
they are pretty cheap and fairly easy to do, just to rule out that possibility.

Good luck!!!!
Chuck

 

[mainstream]

have about 400 hours on my 06. 8.1L B3
This past spring the engine was a little rough especially under load and thought i needed to replace the dreaded cool fuel module. Did fill up boat early in the season with gas from a station that was decimated by hurricane Sandy, so maybe water in the fuel? Treated it, changed the filter. Mechanic said to change the plugs next which i did and the problem seemed to go away for the summer until now.
Now it seems to "miss" under load again.. The miss is Noticeable over 3000 RPM. i also think it idles a little rougher then normal. I did recently get fuel again - and just changes both filters [the disc and the canister in the cool fuel module. the disc filter was gross, the canister looked ok.
The problem seems better but still noticeable. Thoughts on what to do next? do i bite the bullet? Can a mechanic tell from plugging in the engine to a scanner and tell if one injector is bad? could it be wires?

Frustrated... thanks

When you replaced plugs did you do the wires also I had same trouble replaced plugs worked for a while then mechanic called merc and the told him plugs and wires every 3 years or 300 hours do them both at the same time he did and now it's been 2 years no problem. Just my own Experiance hope this helps.

 

[rcmafgny]

The plugs seemed to have fixed the problem, so i stopped there. Sounds like wires is the next to try. Thanks.

 

[Ididntdoit]

Ron - get a fuel pressure gauge to test the problem - there is a spec for what the pressure should be with the pumps energized an then running (i believe 45lbs but im not sure) that is how i found my "cool fuel 3 problem"

 

[Crushin It]

Ron - get a fuel pressure gauge to test the problem - there is a spec for what the pressure should be with the pumps energized an then running (i believe 45lbs but im not sure) that is how i found my "cool fuel 3 problem"

++1

 

[rcmafgny]

Mike,
thanks... q - does the marine engines have an odb port to plug in a tester?
if its is throwing codes, that may help to narrow down if its a clogged injector or ???

 

[Ididntdoit]

You need a rinda scan tool or their software for your laptop...I would test the fuel pressure

 

[rcmafgny]

Ron - get a fuel pressure gauge to test the problem - there is a spec for what the pressure should be with the pumps energized an then running (i believe 45lbs but im not sure) that is how i found my "cool fuel 3 problem"

pressure too high or too low indicates the cool fuel issue?.
if paint flakes are present, how do you go about cleaning the fuel rail and checking which injector may be clogged? or is it a replace and $$