06' 5.0 MPI intermittent fuel issue

[stable46]

Looking for guidance on troubleshooting a fuel issue on my 06 5.0 mpi. Boat will start and run after sitting and then burble and die. Thought I had water in fuel so I discoed fuel supply line at rail in top of the engine to take a sample. 8 KOKO cycles produced about 8 oz of fuel and then it stopped pumping fuel. Can hear the pump come on with each key cycle but for sure stopped pumping fuel. Additional info to add to the mystery - last trip out the motor ran fine until I advanced the throttle at which time it would start to accelerate and then fall on its face until I throttled back. Fuel cooler was rebuilt last year. Showing 3/4 tank which I believe is accurate. Engine serial # 0W357477. TIA

 

[Fun Times]

Sounds like you may want to start off testing what the fuel pressure is by either buying or maybe renting a fuel pressure tester kit from an auto parts store.

An Actron fuel pressure tester kit should help you out that fits your schrader valve size.

Fuel Supply Module, Bravo

Fuel Supply Module, Bravo

www.mercruiserparts.com

350 MAG MPI ALPHA/BRAVO - 0W310000 THRU 0W649999

350 MAG MPI ALPHA/BRAVO - 0W310000 THRU 0W649999

www.mercruiserparts.com

 

[stable46]

Thanks for the guidance Fun Times. Sounds like a good plan.

 

[Bondo]

Thought I had water in fuel so I discoed fuel supply line at rail in top of the engine to take a sample. 8 KOKO cycles produced about 8 oz of fuel and then it stopped pumping fuel

Ayuh,.... Welcome Aboard,...... My 1st step would be to pull the fuel filter, 'n inspect it's contents for anything but clean fresh gasoline,....

 

[dubs283]

Agree with all posted advice. Based on which cool fuel module you actually have there's some difference in filter inspection

Cool fuel module (bravo) is a stand alone fuel cell that has a basket type filter along with a screen element in the bottom. Both filters need replaced at service

Cool fuel III (alpha) sometimes utilized a "boost" or low pressure fuel pump between the spin on fuel water separator and cool fuel/high pressure pump. Another filter in line between the tank and water separator should be in place and replaced as part of regular service. The in line filter is a metal canister style with flared fittings

If you post some pictures of your setup it'll aid greatly for proper troubleshooting advice

 

[stable46]

Ayuh,.... Welcome Aboard,...... My 1st step would be to pull the fuel filter, 'n inspect it's contents for anything but clean fresh gasoline,....

Agree. Did that couple days ago. Filters were fairly clean and no water in fuel. Replaced both and did not help.

 

[stable46]

Agree with all posted advice. Based on which cool fuel module you actually have there's some difference in filter inspection

Cool fuel module (bravo) is a stand alone fuel cell that has a basket type filter along with a screen element in the bottom. Both filters need replaced at service

Cool fuel III (alpha) sometimes utilized a "boost" or low pressure fuel pump between the spin on fuel water separator and cool fuel/high pressure pump. Another filter in line between the tank and water separator should be in place and replaced as part of regular service. The in line filter is a metal canister style with flared fittings

If you post some pictures of your setup it'll aid greatly for proper troubleshooting advice

Thanks Dubs. Will try to get some pics. My module does have both the LP & HP pumps. I had the entire set up rebuilt last year. The in line filter you mention I have never seen. Need to look for that as it could very well be the issue.

 

[stable46]

No inline filter on suction side. Hose runs directly from fuel tank pickup to 90 elbow on cool fuel module.