Thread:

496 mag Ho main fuel pump seizing

Hi All and greetings from Australia, I have a Formula233 fitted with one of the early 496 mag ho 425 hp with a bravo one X diesel stern drive, Last year after a 6 month lay up, I tried to fire up the beast, turned the ignition on, waited for the fuel to prime up, cranked her over but she would'nt burst into life, found the main fuel pump in the cool can housing was seized, replaced with new pump 861156A1, (tested before installation, worked fantastic) installed the pump, removed old fuel filter, filled new filter with premium fuel & installed, then attached aux outboard fuel tank with primer bulb and manually primed fuel system until primer bulb was solid, cranked motor over but it wouldn't fire up, removed flame arrestor on throttle body and got son to spray some fuel as I cranked motor over, she burst into life and ran as long as my son sprayed fuel, later on, I found that the new main fuel pump is now seized I have a new pump on order but I am affraid that this one might do the same and these things arent cheap!! Is there anything else I should be looking for that might cause this? all the wiring is factory standard and never touched or altered, could the pressure regulator be the culprit? I am at a loss, is there any other test I shoukld perform before I kill another fuel pump? sorry for all the questions, am getting stressed cheers from down under, Frank

Originally Posted by OceanDevotion 233

Hi All and greetings from Australia, I have a Formula233 fitted with one of the early 496 mag ho 425 hp with a bravo one X diesel stern drive, Last year after a 6 month lay up, I tried to fire up the beast, turned the ignition on, waited for the fuel to prime up, cranked her over but she would'nt burst into life, found the main fuel pump in the cool can housing was seized, replaced with new pump 861156A1, (tested before installation, worked fantastic) installed the pump, removed old fuel filter, filled new filter with premium fuel & installed, then attached aux outboard fuel tank with primer bulb and manually primed fuel system until primer bulb was solid, cranked motor over but it wouldn't fire up, removed flame arrestor on throttle body and got son to spray some fuel as I cranked motor over, she burst into life and ran as long as my son sprayed fuel, later on, I found that the new main fuel pump is now seized I have a new pump on order but I am affraid that this one might do the same and these things arent cheap!! Is there anything else I should be looking for that might cause this? all the wiring is factory standard and never touched or altered, could the pressure regulator be the culprit? I am at a loss, is there any other test I shoukld perform before I kill another fuel pump? sorry for all the questions, am getting stressed cheers from down under, Frank

Oh, forgot to add, I replaced the primary pump as well and that one is the one I can hear when the ignition is first turned on, its as if the fuel has stopped just short of the main pump and its run dry?? I have disconnected the main pump and tried to connect a positive & negative lead from a spare battery to it and it just shorts out, so the new pump is toast! fried! Kaput!!

Hey you all know what the word "BOAT" stands for? BRING OVER ANOTHER THOUSAND!! cheers Frank

Thanks for your reply "Beer", I just recently removed the failed pump and decided to dismantle this pump for a look see, had to cut the stainless housing in order to dismantle it. Turns out the motor itself was not seized up but in actual fact the tiny pump mechanism itself was locked up & not allowing the pump to rotate, can only assume that it was a manufacturing fault, I will just put it down to bad luck and hope like hell that the new one doesn't do the same!! I did measure the voltage at the pump and it was 12 volts, as was the primary pump,
once again thanks for your input and have a great day cheers from down under, Frank

We replace them with a WELDON 600a. Weldon makes a mini replacement pump also, however we like to run just the one. 👍


Sent from My Boostpower Marine Efi Beacon.