99 Volvo 5.0GL

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
13,691
If you have a carb the proper fuel pressure will be on the low end, the 3-8 psi spec you cited.
A 99 Volvo for sure won't have points, they used the Prestolite BID system on early models with electronic ignition and later they switched to the Delco EST IIRC.
You have an electric fuel pump, check the connections carefully, I think they are in the area where the raw water pump is (belt driven or in the crank pulley area?)
 

Bhuie

Seaman Apprentice
Joined
May 7, 2021
Messages
33
Ok,
So far the fuel line is clear from tank to engine. Fuel pump and filter have now been replaced. Same problem exists where full throttle is fine at start and then after a few seconds starts bogging down. Pull back on throttle and runs fine but top end is gone without bogging down and sputtering. So there are some electric components on the fuel filter and some type of large fuse like box you would see in a car fuse box. Wonder if it could be that or should I move to the holly carburetor? Coil?
 

kenny nunez

Captain
Joined
Jun 20, 2017
Messages
3,476
Try to unscrew the fuel suction pipe out of the tank. There is a fine mesh screen in the tube that may be partially plugged. Pitch the screen, put it back together then take the boat for a ride. Make sure all the fuel connections are tight and leak free.
You do not need a high pressure fuel pump with a carburetor.
 

Bhuie

Seaman Apprentice
Joined
May 7, 2021
Messages
33
Try to unscrew the fuel suction pipe out of the tank. There is a fine mesh screen in the tube that may be partially plugged. Pitch the screen, put it back together then take the boat for a ride. Make sure all the fuel connections are tight and leak free.
You do not need a high pressure fuel pump with a carburetor.
I have done all of that as well. All fuel lines are clean.
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
13,691
You have a fuel pick up tube and an anti siphon valve. That’s the barbed fitting your fuel line attaches to. There is a spring loaded ball inside that valve. It’s there to shut off fuel flow if the fuel line between the tank & fuel pump leaks so you don’t get a bilge full of gasoline. Make sure that valve isn’t clogged and the ball moves freely. I have tested them with a vacuum pump and found that they open at about 1-2” Hg (inches of Mercury). Low pressure fuel pumps should develop about 9-10” Hg.
Fuel tank vent definitely not clogged?
Ever try running it on a separate outboard tank? That isolates the boat fuel system from the engine fuel system
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
13,691
IMG_1450.jpegIMG_1474.jpeg
First pic shows the pick up tube & anti siphon valve second pic is testing them for vacuum leaks….
Vacuum leaks in the pick up tube, anti siphon valve or fuel line can cause this problem as can vacuum leaks at your fuel filter. If you run the boat on a seperate outboard tank you can isolate these factors..
 
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