VST fuel pump
 

Holy geez, I need some help here. Looks like the injection fuel pump has taken a crap on one of my 502's. VST screen is fairly clear and still only have 20 psi at the rail-goes up to 24 if I pull the vacuum line to the regulator (other engine is at 40-48).

Now it seems like most of the Mercruiser injection parts are just GM part numbers, so is there a GM replacement for this pump? Even at BAM the price on this puppy is like 420 bucks-little pricey for a 100 dollar pump.

Any other ideas would be appreciated.

Thanks

Re: VST fuel pump
 

$420 is a good price for a merc.....I paid $495 a few months ago. Its the "merc tax" Hope you find a subsitute.

Re: VST fuel pump
 

Ted, just for grins try swapping the regulators. That pump normally works or dies. Is the VST tank full when you take the cover off?

Yep, Merc is very proud of their stuff !!

Re: VST fuel pump
 

good morning marc........................mark......

Re: VST fuel pump
 

mbam is right check the regulator first, no I dont think that there is a cross over for that pump..it may be a GM pump but I belive that merc modfies it.also check the float and needle and seat in there merc does make a rebuild kit for those and as long as your there you might as well

Re: VST fuel pump
 

Thanks for the advice guys. I did have a full tank when I opened it and the low pressure was at idle so there was very little fuel consumption anyhow. I guess I'll do a regulator swap and then send you some more money Marc :D one way or the other, since the o-ring decided to grow as soon as I removed the cover :rolleyes:

Re: VST fuel pump
 

One way to test the regulator and pump is to momentarliy clamp off the return line and see if the pressure goes way up. That will tell if the fuel pump is able to make full pressure and the regulator is not stuck open. Not all fi systems have a return line. This only works on a return system.

Re: VST fuel pump
 

Ted I have a pile of those VST pumps if you want to try one I take them off the early engines and put a bigger pump and cooler on. Tyler

Re: VST fuel pump
 

Scott, the only exposed hose on the Merc system is a reinforced, crimped hose similar to p/s hose on a car. As you probably know it isn't a good idea to crimp it, the rest of the run is in the fuel rail itself.

Tyler, thanks for the offer, if it looks like a pump I will be in touch and see if I can lessen your pile a little :D I really appreciate it.

Re: VST fuel pump
 

you can't be far off the mark. Recently while servicing a similar system on an outboard I noticed the Mitsibushi emblem on top of the pump. They supply the pump to Mikuni who intern sells the entire intake assembly to Suzuki, Yamaha, etc. Went to the car dealer and bought the $300. pump for a $125.00