2008 VP 5.0 GXI - Fuel Pump?

[JimPTx]

I was on the lake yesterday in a 2008 Larson with the 5.0 GXI package. Off the trailer it ran great. We shut it down to swim for a bit, and it wouldn't start after that. It cranked fine, and spun over fast. After several tries, we were able to get it to fire. It idled rough, and didn't want to run without some throttle. There was also a "sucking" sound whenever it would fire. It felt a lot like a flooded carb motor.

Doing some reading, it sounds like the low pressure fuel pump failing (or inlet stopped up) could be a possible reason for the hard starting. Has anyone faced this before, or have any suggestions on troubleshooting?

 

[Bondo]

or have any suggestions on troubleshooting?

Ayuh,..... Welcome Aboard,..... Step #1 is change the fuel filter, 'n inspect the contents of the ole one for water, 'n crud,.....

 

[alldodge]

Howdy

After idling rough and not wanting to run, did it come back to life and run fine again?

 

[Thalasso]

I was on the lake yesterday in a 2008 Larson with the 5.0 GXI package. Off the trailer it ran great. We shut it down to swim for a bit, and it wouldn't start after that. It cranked fine, and spun over fast. After several tries, we were able to get it to fire. It idled rough, and didn't want to run without some throttle. There was also a "sucking" sound whenever it would fire. It felt a lot like a flooded carb motor.

Doing some reading, it sounds like the low pressure fuel pump failing (or inlet stopped up) could be a possible reason for the hard starting. Has anyone faced this before, or have any suggestions on troubleshooting?

When that pump goes bad you will hear it long before it hits the crapper. It will start to whine and get hot to the touch.
Don't be in such of a hurry to even think it's the pump. There $600+ depending where you buy it. You can't buy just the low side. It comes as a unit.

 

[bajaunderground]

Search on on iboats for 'Volvo Penta fuel pump' there's a plethora of related posts of items you can look at before you replace the whole fuel cell. It can be as simple as Bondo suggested (replacing fuel/water separator filter), crud in your screen from the paint that was used to coat the aluminum cell assembly, bad anti-siphon valve...the list feels endless! I had an issue of the by-pass on the thermostat housing partially clogged from an old impeller...the gas got too warm and would boil (I'm at 4,800' and we use 85 octane fuel with 10% ethanol. I only use 91 octane as the 85 boils at 90*). It caused a vary similar condition. Once I replaced the fuel cell and cleaned the by-pass, it hasn't happened since. Pull the littlest hose off the thermostat housing with the engine running (on clean-out or muffs or in water and make sure you have flow to the cooling jacket on the cell?!


​Cheers,
Brett

 

[ericga]

You may also want to check the fuel pressure regulator for restriction. See "service bulletin P-23-7 no. 3 version 1".

 

[JimPTx]

I was able to spend some time on it last night. Ericga - you nailed it.

First - replaced the fuel/water separator. With key on, but not running, I had 9 psi on the low pressure pump and 50 psi on the high side at the fuel rail. Changing the filter helped to get it started, and I rechecked pressures with the engine running. Low pressure remained at 9 psi. On the high pressure side, it started at 55 psi, but began creeping up. I finally shut it off at 95 psi with the pressure still rising.

I then pulled the fuel pressure regulator. The screen had some kind of particulate on it. It wasn't black paint - possibly ethanol goop?. I washed that off with carb cleaner, reassembled, and it seems to be running well. It starting easier and is idling very smoothly. Hopefully we'll get it back in the water in the next couple of days and be sure its fixed.

Thanks to everyone for the suggestions! It was a great help!

 

[ericga]

Thanks for sharing your findings. Let us know if all is good after a water test!

 

[JimPTx]

That appears to have been the fix. We ran it around for a few hours, pulled a wakeboarder, etc. with no issues. Thanks again for everyone's input!