2000 2800 SCR fuel pump

[Rice's Raft]

For about a month now after about an hour or so at cruising speed my boat starts to loose power. With 6 people aboard it takes a long time to get up on plane, before a month ago it had no problem planning with 9 people. The tach will drop & rise, drop & rise & today it backfired twice. I had to idle back to the marina and after running around for about an hour to get my fuel pressure gauge & timing light I checked the fuel pressure. It was steady at 45 psi. But since I bought the boat 2 years ago the fuel pump seems loud to me when you turn the key on & it primes. Almost like a grinder. When the engine is running I don't notice it though. Does everyone's pump sound like that? BTW, the timing was right on, I put a new cap & rotor on before this trip. Plugs were replaced at the end of last year, pulled 2 from each side the ceramic is white. I bought an ignition coil & mounted it beside the original coil, switching back & forth changed nothing. Vacuum is steady 16in hg. When I lost power today I put it in neutral & removed the fuel filler cap, no air rushed & still no power right after that. I checked for codes today & there were none. My mind tells me fuel pump overheating, ignition module or ecm. I'm going to run it again Tuesday morning with my fuel psi gauge & see what happens. My luck it won't act up Thanks for any help with this!

[Rice's Raft]

I should've told everyone it's a single 7.4L MPI

[mmwjr]

I do not have any first hand experience here but from reading similar issues from others it sounds like a cool fuel issue. Another thought is water in the fuel, did you gas up around the time this started?

[Rice's Raft]

Thanks for the info. I only fuel up in my marina & no one else is having a problem, when it first happened I replaced the fuel filter, I tested the gas that was in it & no debris or water. I'm trying not to over think this but I'm wondering if maybe my pickup is cracked in my gas tank...the first time this happened I had a full tank starting out, 9 people on the boat I was running at about 4000-4200 rpm for about a half hour, I made a left turn at cruising speed not a hard banking turn just gradual right after I straightened out it acted up...yesterday a full tank, 3 people, ran good, at about 3/4 of a tank a did a hard left hand turn then after coming out of the turn a went to wide open throttle then it started acting up worse than it ever has...I'm gonna run it tomorrow with my fuel psi gauge on & see what it does...

[mmwjr]

Are you a NASCAR driver, always making left hand turns?

It will be interesting to see what the fuel pressure is doing. Not sure why a cracked pick up tube would would act this way, I would not think turning would matter unless the gas rolls away and air is getting sucked in. Does it recover after a short time?

Electric pumps do not like to be ran dry.

[Rice's Raft]

If I was a nascar driver I wouldn't be fixing a 2000 2800 it did not recover yesterday wouldn't come off idle without the RPM surging & misfiring...tomorrow morning I'll dive into it hopefully it's acting up enough to find the problem...I'll report my findings tomorrow night

[Rice's Raft]

After running the boat constantly for over an hour, making left & RIGHT turns, going to wide open throttle then back to cruising speed it never missed or fluttered! Ran like a top! 3800 RPM at about 26mph for over an hour. Just before I went back to the marina I stopped & timed how long to plane. With 3 people under 20 seconds. I had a timing light on the coil wire & a fuel pressure gauge on it the whole time and no problems. I'm just going to run it with those on all the time...they fixed it! The only thing I wonder about is on my fuel psi gauge, the needle bounces about 2-3 psi the whole time but the pressure was always within specs. My gauge doesn't do that on a car. Hate not finding anything wrong today because I'll always be anticipating it on future trips...

[mmwjr]

Murphy works like that.

I would think the bouncing fuel pressure would be an indicator of an abnormal condition.

[mikembs]

have you checked the fuel lines? i had a fuel problem on my SCR 2700 7.4l carb, they rebuilt or replaced every thing except the lines. then i replaced the lines and my problems were gone. the ethanol in fuel these days is hard on the older fuel lines.