200 hpdi bogging down again

[mizar]

Make sure your fuel filter cannister is tight. I had the same problem and found that air was being sucked in around the loose fuel filter (external fuel filter prior to engine)

[Felton]

The vst filter looks great, but now I am having problems getting it all back together. The filter is hitting the bottom of the bowl. The collar is on there in the correct positon (I think) with the notch down so it fits over the ridge. The only thing I can think of is to replace the O-ring above the collar.

[jb123]

you didnt say what year motor but how many lp pumps do you have, 2 ?

you said u unbolted it and gas came out... you need to pump ball and see if it comes out... of both if you have 2.

they work on crankcase pressure to supply vst, so motor has to be turning over to supply vst.

what is the level of the motor filter when this happens, poor running ?

[Felton]

2000 hpdi I have two mech. fuel pumps. I checked both of them.

Are you asking about the fuel level in the clear plastic bowl or the level of the fuel filter itself.

[Felton]

Ok so I was double checking myself today and I must not have pumped the primer bulb when I checked the other fuel pump it is leaking also. So befor I replace this fuel pump again what would cause both of my lp fuel pumps to go out. Air getting into them? I replaced this pump 6 months ago. The other pump I replaced a week ago.

[Felton]

Replaced the lp pump today It is back to the same if I pump the primer bulb it will rev. up to about 3500 rpms. after that it starts to bogg down. What will make my lp fuel pumps go out so fast?

[Tucker]

Keeping this one at the top of the list. Need earlier question answered: What should be the fuel level in the engine mounted fuel filter?? I believe my level is about halfway up. I've never had the cowl off at high speed. Need some of the heavyweights to sign in and comment. Where are you bigfish, jb, boats.net???

[Felton]

Thanks tucker mine is full now and it has stayed at full.

I read that the o2 sesor could be doing something to hinder it so I will try cleaning it.

[mrv8outboard]

One thing to keep in mind is that the low pressure pumps are driven off cylinder pressure and vacuum pulses. These are on specific cylinders. You can have good compression at the combustion chamber but scuffed piston skirts will limit the pressure and vacuum that a cylinder can create, hence limiting the fuel pumps ability to pump. put a 5/16 tee with a piece of clear hose between the low pressure pumps and the VST and put a fuel pressure / vacuum gauge on the tee and run it. Look for air bubbles in the line and get a pressure reading. You can do the same at the line just before the engine mounted filter. This side you will be looking at a vacuum reading and hopefully no air bubbles.

Have you disassembled the pumps that failed? What is the failure? Do they look burnt at all? If so maybe a lean cylinder back fire burning them up?

[Felton]

I pored out half the gas in the fuel filter and poured in seafoam. It seems like it runs fine on the half gas half seafoam mixture but as soon as it runs out of sea foam it starts to bog down again. still looking for more ideas

[mrv8outboard]

Get a portable tank. Fill it with new gas and try it. Sounds like bad gas.

[Felton]

Let this be a lesson to me. I am hard headed sometimes. I guess I must have knocked my fuel line loose when I replaced the vent line and fill line it was pulling air. I should have done the vacume test in the first place I just didn't have the things to do it with. I guess I should purchase the things necessary now so I will have it in the future.

I am sure I will be back but for now its off to the races...

Tight lines and good fishing. Thanks to all.

[Tucker]

Ok, how could sucking air in the fuel line take out the low pressure fuel pumps?