150 Merc Fuel Pressure Issues

[dpomp]

I hope someone can help me !
I have a 2000 Mercury 150L EFI. It sat for about 2 years and I am trying to get it running. I have pulled off and cleaned the VST tank, replaced the high dollar fuel pump in the VST tank (ouch, would not clean up), and the VST gasket. I have cleaned the water sep. and replaced the primer bulb line from hull to mech. fuel pump. When we turn it over the cylinders are getting no fuel at all.
Problem is after all of this, it will not hold fuel pressure. When you turn on the key, the pump runs for about 30 seconds then stops. During this time the fuel pressure will run up to about 38 psi and stay steady. As soon as the pump stops, the fuel pressure drops like a rock. When you turn the key on the pressure will jump back up. I ran a hose from the outlet of the VST tank to the fuel pressure reg. basically bypassing the fuel rail and injectors, and still the same result. IS MY NEW FUEL PUMP NOT HOLDING back PRESSURE???

One thing is that the primer bulb does not seem to pump up rock hard, and it wont hold steady pressure. Just put my ear on it, and when you pump it up, you can hear a bubbling/hissing noise in the primer bulb.
I have to continue to pump it to keep pressure on it. Is the new primer bad?

Have any of you had this problem before?
Thanks for any help

 

[dpomp]

Re: 150 Merc Fuel Pressure Issues

Still need some help, but have made progress.

Pulled off ECU and injectors. Sprayed w/carb cleaner and cleaned inj. screens, they were not clogged, or no buildup on them at all.
Put back together, and now it STARTS. But it will only run for about 10 seconds. It does not sound like it is hitting on all cylinders. It idiles rough, then dies. Turn key off, then turn key on and fuel pump runs for about 20 secs then you can fire it up and it does same thing.
Am I missing something?
Thanks for any help, I will keep trying.

 

[leaky]

Re: 150 Merc Fuel Pressure Issues

I've never had to spend much time trouble-shooting EFI fuel issues, so there may be something obvious I'm missing, but here goes.

I'm thinking you do have a fuel delivery issue, and if not it's a straight up fuel issue..

Make sure you put the new primer bulb in the right direction (sorry ).. and also that any other one way valve's in the system (up to the fuel pump) are either bypassed or operating correctly. This would include any "anti-siphon" valve which might be installed on the fuel tank itself.

Next verify there isn't anything causing a vacume; it's not uncommon for permanent fuel tank vents to get clogged from bugs (seriously, bugs nest in the screens) and/or corrosion. Such a vacume can cause strange things.

After 2 years your fuel is probably junk (the whole ethanol thing).. water in the fuel tends to cause problems that are similar to fuel delivery. If there was much water in the seperator you probably have a couple inches of water in the bottom of the tank. Only solution at this point to that is pumping the tank dry...

If all else fails get yourself a 6 gallon jerry jug with it's own fuel line. Fill it with new fuel. Drain the fuel system completely and clean those injectors back out, then re-attempt. If it works you know it's either your fuel or setup in the boat itself.

Jon

 

[Faztbullet]

Re: 150 Merc Fuel Pressure Issues

What you have is a varnish coating in the fuel rail and injector pintle. Remove injectors,rail, regulator and ecu and send to Tony & Linda @ www.brucatosvs.com. They will clean and balance injectors,check ecu for bad driver board and clean rail and regulator. The injectors cannot be cleaned correctly unless power is applyed to them to withdraw pintle needle. I send all my customers parts to them to service and several Iboater's have had their service and suprised and how well engine performed when parts was returned.