2007 df90 fuel issue

[wblack]

OK guys I can't believe it....... took the boat out this weekend and had basically the same issues.

I am thinking the low pressure fuel pump is bad. Up to about 2000 rpm's it runs smooth as all get out, then it just starves for gas it sounds like. I can give it gas out of gear and the rpm's go up and down until finally it quits. My guess is the low pressure fuel pump is not keeping up with fuel demand and the reservoir is going dry?? Any other ideas after all the fuel system cleaning I recently did?

I will take the LP pump off and check it. Question about that is the manual says make sure the crank is at TDC on the compression stroke; is there an easy way to do this? I assume I would take the number 1 spark plug out and rotate the engine until I feel pressure and line the marks on the flywheel?

Thanks in advance for you guys help!

[Solarman]

Wblack, if low press pump is at fault, you should be able to pump the primer bulb by hand, to know if it is the problem. It may be that in your cleaning, you missed something? Did you remove the needle valve seat (sometimes blocked on the backside, often overlooked)? Or, possibly you still have a fuel line deteriorating from ethanol use, causing new blockage? And yes, it is possible that some gunk was inside the low pressure pump, just waiting to push it back into the vst?

Not trying to rain on your parade, but trying to be honest. Did you run any additive in your fuel once cleaned thoroughly? This should be a must.

Good luck, post back when able on what you find.

[wblack]

Wblack, if low press pump is at fault, you should be able to pump the primer bulb by hand, to know if it is the problem. It may be that in your cleaning, you missed something? Did you remove the needle valve seat (sometimes blocked on the backside, often overlooked)? Or, possibly you still have a fuel line deteriorating from ethanol use, causing new blockage? And yes, it is possible that some gunk was inside the low pressure pump, just waiting to push it back into the vst?

Not trying to rain on your parade, but trying to be honest. Did you run any additive in your fuel once cleaned thoroughly? This should be a must.

Good luck, post back when able on what you find.

Great points; I did forget to state that I could pump the primer bulb and the engine would catch up. I assume that's a tell tale sign of the LP pump? I did clean the needle valve and inspected it for wear while we had everything apart. I am thinking as I type.... I don't think we left one piece of old hose but maybe we overlooked one of the short ones somewhere.

Maaaan, I hate the thought of trash being in the VST again and I thank you for being honest; I don't expect anything less. Thank you.

I ran injector cleaner the first half tank (whole bottle) but nothing else. Do you recommend additional additives?

[artdf175]

let me chime in and add this with regards to the bulb
sometimes if you have to pump the primer bulb --it can be the result of a couple other problems -before you get to the bulb
start with the fuel tank venting. just be sure the bugs like spiders have not set up shop .. if the fuel system is not venting correctly the primer bulb gets soft, indicative of a vacuum
the other thing could be a air leak in one of the hose connections

earlier you mentioned you put in all new hoses.. to rule out a fuel hose problem- you can take the engine connector off the end of the hose, put the hose in a glass jar and pump the primer bulb. once the air is out, you should not have any bubbles.. pump hard .

one of the other things I recently found is to watch the small inline fuel filter .. if it is not full of fuel all the time when running.. again a fuel line problem.

here is another way of checking the LP fuel pump.. put a piece of tubing on the -out- side and start the engine. again put the fuel line in a container to catch it.. if it pumps out a good stream- not likely the pump.

good luck
art...