diln911

Hey Guys, Im am new to the forum as an owner, although I have been reading and checking out offshoreonly.com for some time now. Im hoping some experts can give me advice. I recently purchased a 1996 32 Fountain fever with twin 502 mags. The first time I ran the boat, I had not been informed that there was an issue with the fuel gauge sticking. Within the first 10 minutes of running my new boat, I ran it out of fuel. When I noticed it was sputtering I shut it down. Never thought I actually ran it out of fuel completely. Anyway, I put 100 gallons of fuel in it. The Starboard motor fired right up... no issue. The Port side motor would not start. I checked the fuel filter and it was dry. I primed it and put it back on. The motor ran, and the boat ran great. I got back to my river house and parked it. Two hours later I went out to start it and it wouldnt start. It appeared as if it was losing its prime. One mechanic suggested that I check to see if there was a one way check valve in the tank and to check it by blowing on the fuel line coming off of the low pressure fuel pump, and if I hear bubbles in the fuel tank, that valve is not closing and allowing fuel to gravity feed back in to the tank. Also, he suggested there could be some issue with one or both of the fuel pumps. Anyway, I can turn the motor over and over and over with the starter and eventually it will fire and run. Almost as if the low pressure fuel pump is pulling a prime but it takes a while to get it. If I am running along at idle with the motor in gear, after putting along for about three minutes, the motor cuts off, and you have to reprime it to start it. Any thoughts? I was thinking about just putting a one way check valve in the fuel line on the high side of the gas tank, but before the filter. I was also wondering if I could have damaged the low pressure fuel pump by running it dry? Anyway, any help or ideas to try would be appreciated.

Thanks so Much

Jim Courtney
Richmond, VA

getrdunn

iTrader: (7)

these 502's are carbed right. if so sounds like you may need to frreshen up your carbs. regardless of your fuel situation before the carbs you should still have fuel in the bowls. with a couple of pumps you should have plenty of raw fuel in the intake to fire the engines and quickly prime on there own. can you see the fuel come out of the squirters when you pump the throttles?

getrdunn

iTrader: (7)

i wouldn't suggest the check valves without finding your problem. if these are non carbed someone will have advice as to move forward from here.

diln911

These motors are fuel injected 502 mags. I know there is a low pressure fuel pump that runs off of the crankshaft belt driven, and then there is the high pressure electric pump at the top of the motor. I did not check to see if there was a check valve in the tank on the starboard side, but I did blow back in to the port side fuel line to the tank and there is definitely not a check valve in there. The fuel filter at this point seems to be staying primed, when I take it off at this point it is full of fuel, versus after I ran it out of fuel and that one time it was empty. The boat wasnt doing any of this before I ran it out of fuel, so is there anyway I could have damaged the low pressure or high pressure fuel pump by running it out of fuel.

HiPerf2000

iTrader: (2)

its called a VST pump. do a search here for more info on troubleshooting.

diln911

Ok so are you suggesting that the VST is the problem? Or are you just telling me the proper name of the pump? Would the VST or could the VST go bad from running it out of fuel, and if it did, would these be the symptoms?

Thanks so much

diln911

Hey thanks for heading me in the right direction. Looks as if this is a common problem. The Port side motor that I am having trouble with is an original 502 mag from 1996, but the Starboard motor is a 2006 factory 502 mag replacement because the original starboard motor seized. This sounds like the problem of running out of fuel and the problem of the motor cutting off on me are two different issues, and it was coincidence that they happened at the same time. The Port motor is vapor locking which is a common problem with the early VST engines when the temperature, or more specifically humidity, is high. Mercury seems to have solved the problem on the newer motors, which explains why I have not had any issue with the 2006 motor. Anyway, Im heading in that direction to try and deal with the issue of the VST.

Thanks again everyone.

Jim

US1 Fountain

iTrader: (1)

My '99 502's have had a couple of vapor lock issues this summer after the motors have been ran, then left off for as long as several hrs. Really bad when hot out. Several houseboaters on our lake have been having the same problem this yr with their generators.
Both motors would crank, and fire, but die as soon as any throttle applied, till they wouldn't even start. Took as long as 30 min to get them started once. Once the would run with throttle applied, they were instantly fine. Both motors have the updated VST pumps too, so that doesn't neccesarily mean that is the cure. It's the ethanol in the fuel this yr. causing all our problems.

diln911

Ok, thank you for your feedback. I was planning on pulling the pump apart and checking to see if there was trash in the fine filter within the VST high pressure pump. I keep being told its possible that is the problem. Also, with high temps I have been trying to run the blower fan on the whole time unless Im running 50 or better, and at slow speeds I have been raising the hatch a little bit to get air in there. I am also planning on running a can of marvel mystery oil in there. Reading this forum a bunch of people have suggested that, in addition to some stabilizer. Perhaps this assists with dealing with the ethanol.

Jim