johnson 225 ocean runner with possible fuel issues?
im back for a little friendly advice again, heres the scoop...
i have a friend that bought an 1986 22ft boston whaler revenge with a 1994 johnson 225 ocean runner V6.
it still has the vro system in place as well as the oil tank full of oil
it sat for a few years before he bought it, then sat a few years after he bought it, well hes retired now and ready to get it up and going. i came over to help him get it going, we changed all 6 plugs as well as the water pump impeller just to be safe. since that boat has a 70 gallon under deck fuel tank, just for testing purposes we took the small 6 gallon tank of 50:1 premix fuel from his aluminum jon boat, and just took the fuel connecter end that hooks to the motor off, then disconnected the fuel line that comes from his under deck tank before the fuel filter, then connected the two up so the motor was feeding off the small 6 gallon test tank.
i pumped up the bulb, turned the key on, pushed it in for the fuel enrichener, turned the motor over, it spit and sputtered a few times, then roared to life and sounds like king kong on cocaine!
it sounded great..... for about 20 seconds or so, then it slowly dropped rpms and died out. we pumped the fuel primer bulb and fired it up again, and same thing, sounded great for a little while, then the rpms dropped off and it doed again. we kept doing this hoping whatever was the problem might clear itslef up, but it didnt. we could crank it, and if i pushed in the key occasionally it would stay running, but would then drop rpms and die out, same thing would happen if i tried to rev it a little bit, it would rev up, drop rpms, then die out. in most all of my previous experiences over the years with cars trucks and boats, that has always been a faulty fuel pump not putting enough fuel to the carbs.
we both came to the conclusion that the fuel side of the vro wasnt pumping, now he isnt crazy about the vro on that motor and was wanting to do away with it anyway. he was even less crazy about the price of a new vro pump.
so here is my questions,
is it a fuel delivery issue like i am suspecting? or does anyone suspect it could be something else?
he wants to do away with the vro pump anyway and just premix his own fuel, so what fuel pump could we put in place of the vro?
ive already searched for putting an electric low volume fuel pump in place of the vro pump and it seems that is a hot button issue with some people, so what pulse diaphram pump would be a relative inexpensive fix and still push enough fuel for that V6?