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Cadet
- Joined
- Jun 30, 2009
- Messages
- 21
My 2003 Mercruiser Alpha 5.0 serial number Om626769 has me stumped. I replaced the fuel pump with a Quantum E11004 recommended by one poster on this forum. I also replaced the fuel pressure regulator inside the Cool Fuel 2 module plus the one on top of the rail. Two fuel pump regulators? Oh well, it was in the parts diagram. I have replaced the fuel filter plus I have ran a hose from a separate tank directly into the inlet port on the filter thinking that the fuel cut off solenoid was somehow plugged up. When the key is turned on the pump runs for a few seconds and the pressure at the rail is 29 lbs. When the engine starts the pressure drops to about 25 lbs. The needle of the pressure gauge jumps around some. Stated pressure in the manual I have says it should be around 40 lbs. Although I have not ran the boat on open water (it's on the trailer) It seems to run and start very well. I'm thinking that under load the engine will not produce much power considering how different the pressure is from the stated required pressure in the book. I even tried a different pressure gauge thinking my old gauge was giving false readings....it was not. If I remove the vacuum hose from the pressure regulator the reading goes up about 5 lbs and from what I've read this is good, the regulator must be working. The only thing I can think of now is the new pump must be at fault and not able to put out the correct pressure. This Cool Fuel 2 module is practically impossible to remove and install. It takes literally hours to get it back in.....back breaking work in this heat. Would appreciate anyone who could think of something else before I go taking this pump out again.
