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Volvo Penta fuel issue

davek258

New member
Greetings. This is my 1st post and I could really use some help. I have a 2003 Hurricane with a 5.0ltr Volvo Penta that is carbureted and has a single low pressure, electric fuel pump. A bit of history on the boat; I got it from a family friend after it fell off of his shore station and ended up with the motor under salt water for several hours. Boat was pulled out and all fluids changed. Fuel tank was drained and cleaned. New coil, distributor, plugs, starter. Boat sat for several months before I got it. When attempting to start the boat, a massive amount of fuel gets dumped into the carb. I had the carb rebuilt twice by two different people and same problem. There is no external fuel pressure regulator that I can find so I thought perhaps there was an internal one that went bad in the fuel pump. Hooked up a pressure tester to the fuel pump and it's putting out over 40lbs of pressure, instead of about 8 that I believe is called for I replaced the fuel pump with a new one and same problem; gas getting dumped into the carb at a tremendous rate and the pressure on the new pump is about 40 also. The new pump was specifically made for a carbureted, low pressure system. Any thoughts? What should the voltage be at the fuel pump?
 
At idle pressure can vary, 5-8, can drop a bit at higher RPM's (like.5 lb ish). Since the boat was submerged, and sat for some time, I'd be checking every aspect of your electrical system. When you turn your key to on (not to start), what is your voltage at the alternator output lug? And when you crank engine, what is the voltage at that same point?
 
The voltage at the fuel pump should be at/near 12.


If the pump is putting out 40 psi, then it's the wrong pump for a carburetor..... especially after having tried two of them!

The Carter P4594 or P4070 appears to be a decent carburetor fuel pump.

shopping



The higher pressure FI fuel pump will look similar to this one.

shopping
 
At idle pressure can vary, 5-8, can drop a bit at higher RPM's (like.5 lb ish). Since the boat was submerged, and sat for some time, I'd be checking every aspect of your electrical system. When you turn your key to on (not to start), what is your voltage at the alternator output lug? And when you crank engine, what is the voltage at that same point?

I will check the voltage at the alternator later this week. I will check with the previous owner but I believe that the initial fuel pump that was on the boat when I got it was the same one that was on it prior to being submerged. Prior to being submerged the boat ran well. It was sometime after that when they were attempting to get the boat running after it was out of the water, that this sudden amount of excessive pressure developed. The fuel pump that was initially on the boat when I got it and the new one that I replaced it with are long, round and black in color with a 2 pin connection. The seller of the new pump purchased clearly states that it's for low pressure carbureted engines. I was wondering if perhaps the pump could be getting excessive voltage, causing it to pump extremely hard/fast? Is that possible? Anyway, I will check the voltage and report back. Thanks much
 
While under the assumption that some here believe that increased voltage could change the pump's pressure....... how could this change the fuel pump's output pressure, and in particular from 4 to 7 psi to 40 psi?
 
The voltage at the fuel pump should be at/near 12.


If the pump is putting out 40 psi, then it's the wrong pump for a carburetor..... especially after having tried two of them!

The Carter P4594 or P4070 appears to be a decent carburetor fuel pump.

shopping



The higher pressure FI fuel pump will look similar to this one.

shopping
Both the old and new fuel pump look like the one above (round and black). The old one worked fine until the boat was pulled from the water, but both are putting out excessive pressure and flooding the carb immediately. The new one , according to the seller, is for low pressure, carbureted motors only. I suppose perhaps, I should run the old fuel pump directly from a battery using jumper wires and check it's pressure and do the same with the new pump. The question I have is why would the old fuel pump run the boat for years, then suddenly when it is pulled from the salt water, create excessive pressure and why would a new one do the same. I should mention that not the entire boat was submerged, just the engine. The boat slipped off a shore station, with the back end going under. Thanks for any help. I'm pulling my hair on this.
 
I understand that both the high and low pressure pumps look the same, and perhaps the seller sold me a high pressure pump instead of a low pressure one, but what would have caused the original pump that was working fine on the boat to suddenly create a significant increase in pressure?
 
When the key is turned to the on position I have 12.6 volts at the alternator lug. When crankiung the boat the voltage varies between 9 and 10.
 
I tested both the old and new fuel pumps, independent of the boat; testing them directly from a battery. I used a different pressure tester. The original fuel pump put out 35lbs of pressure and the new one tested at 96lbs. I received a refund on the new fuel pump and ordered another new, low pressure fuel pump. I will test that before I install it on the boat to see that it reads somewhere around 9lbs
 
Since there is no in-line pressure regulator, I'm going to assume that there must be some sort of internal pressure regulator in the fuel pump that went bad when the boat was submerged. As for the new fuel pump that showed 96lbs of pressure, that must be a high pressure pump that was sent to me in error. I am still awaiting another low pressure fuel pump to arrive and hopefully this will test out at a low pressure before I install it in the boat.
 
Put a new, low pressure fuel pump on the boat and it's not flooding the carb as it was, so that problem is fixed. Still can't get it to keep running. When looking in the carb and hitting the accelerator pump, it's getting a squirt of gas like it should, however it won't start on a regular basis. Timing is on and all cylinders are getting spark. I've had it running for about 10 seconds on 6 different occasions but it will not stay running. Fuel filter was just replaced and even when squirting gas in the carb, It won't stay running. Also, you have to crank it for a long period of time before it will start, if it will start at all (not good for the starter, I know). Compression was low, but my mechanic said that was from the engine getting "gas washed". I removed all the plugs, cranked it over to get excess gas out, squirted a little oil in each cylinder and the compression came back up. Still can't get the boat to run steadily.
 
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