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matt
04-10-2011, 08:18 PM
First time out today, and had some fuel delivery problems. It had a new fuel filter and fresh gas, everything ran fine, execpt at WOT. up to 3600 rpm, everything was great, but fell flat after that. Coming back in to get a fuel pressure gauge, we pulled the filter and blew it out. No trash but the boat started running better. Went and got a new filter and gauge, pressure was approx 30 psi at idle, 36 psi at 3000, and 22 psi at WOT. I got home, no trash in the tank, lines were clear, clean filter. Does anyone have any ideas?
Thanks

Engine Nut
04-10-2011, 08:55 PM
First time out today, and had some fuel delivery problems. It had a new fuel filter and fresh gas, everything ran fine, execpt at WOT. up to 3600 rpm, everything was great, but fell flat after that. Coming back in to get a fuel pressure gauge, we pulled the filter and blew it out. No trash but the boat started running better. Went and got a new filter and gauge, pressure was approx 30 psi at idle, 36 psi at 3000, and 22 psi at WOT. I got home, no trash in the tank, lines were clear, clean filter. Does anyone have any ideas?
Thanks

The fuel pressure on that engine should be 36-39 at idle, 38-42 at mid range and 40-45 at WOT. Try kinking off the return line and see if the pressure comes up. If it does, your pump is probably OK and your fuel regulator is probably the culprit. If the pressure doesn't come up, the pump is probably in need of relacement.

JimN
04-10-2011, 09:34 PM
First time out today, and had some fuel delivery problems. It had a new fuel filter and fresh gas, everything ran fine, execpt at WOT. up to 3600 rpm, everything was great, but fell flat after that. Coming back in to get a fuel pressure gauge, we pulled the filter and blew it out. No trash but the boat started running better. Went and got a new filter and gauge, pressure was approx 30 psi at idle, 36 psi at 3000, and 22 psi at WOT. I got home, no trash in the tank, lines were clear, clean filter. Does anyone have any ideas?
Thanks

Did you check the screen at the fuel pump inlet? This sounds like yours is clogged.

matt
04-11-2011, 06:17 PM
I was hopeing the whole way home that it was the screen, but it looked brand new. I think that I am going to replace both. The boat is 16 years old, and it couldn't hurt. I bought new fuel and return lines today, they were $88. Seemed high, but thats cheap insurance. I'll keep ya'll posted, it might help someone one day. thanks Engine Nut and JimN.

André
04-11-2011, 07:56 PM
88$ is quite cheap IF it fix your problem.
Did you try engine nut trick first ?

JLeuck64
04-12-2011, 12:24 AM
Inlet filter (located on top of the fuel tank) has an AC Delco part number 25171391.

matt
04-12-2011, 08:41 PM
Andre, whats the engine nut trick. As far as the fuel lines, I figured they are 16 years old, changing them is cheap, gas in the bilge can be expensive.
JLeuck64- I don't have a filter at the top of the fuel tank, my line is threaded directaly to the pick-up.

André
04-13-2011, 07:09 AM
Andre, whats the engine nut trick. .

Post #2......

Jorski
04-13-2011, 11:09 AM
FWIW...I had the same problem a few years ago...it turned out that there was ton of junk in the fuel tank.

It needed a complete clean out.

matt
04-13-2011, 09:55 PM
Sorry Andre, I realized what you were saying right after I posted. Thats what I was hopeing Jorski the whole way home. I pulled the tank and it looked great. 0 trash in the tank or on the screen. I have a new pump should be here tomorrow. It will solve the problem if all the testing is correct. I appreciate everyones help, this is what makes being a Mastercraft owner so great. Everyone looks out for everyone else.

JimN
04-13-2011, 09:58 PM
Sorry Andre, I realized what you were saying right after I posted. Thats what I was hopeing Jorski the whole way home. I pulled the tank and it looked great. 0 trash in the tank or on the screen. I have a new pump should be here tomorrow. It will solve the problem if all the testing is correct. I appreciate everyones help, this is what makes being a Mastercraft owner so great. Everyone looks out for everyone else.

Did you look at the anti-siphon valve at the top of the fuel pickup? Also, check the fuel pickup tube for debris.

matt
04-14-2011, 09:19 PM
Yea Jim, I hate it but it's the fuel pump. Yhanks for your help ,