WTH? fuel issue? weird! fuel pumps going out?
 

454 mag mpis with around 80 hours new long blocks in 2012. 2x on 98 33outlaw. 2 injectors were replaced and rest flow checked and cleaned. new exhaust, etc. Thinking stock fuel pump fuel cool crap. 576 hours on boat.

Quick history... filled up in January when prices dropped out but caused some mild vapor lock with the winter mix fuel. Had already ran fuel returns to tank. Only mild bc they still cranked unlike my previous experiences with vapor lock when engine would not crank at all.

ok, so I bought 2 holley fuel pumps and filters and installed as booster pumps to eliminate this issue.
First time out ran great, fixed the issue, didnt really run her that hard bc it was fairly rough but I thought I remembered running over 60, but didnt push wot.

Next poker run, we were running hard cruise at around 44-4500 and I pushed to wood and she fell on her face, rpms fell to 4k and then recovered. At first when I pushed to wot.. nothing, then after a few minutes, I gained rpms but woudl max at 45-4600 and loose power. Normally, I could push to 48-49 with a load.

Once I got home I dumped both fuel separator,filters and didnt notice any trash. Thought the fuel pumps werent keeping up with the 4psi 72gph rating should be fine, but wanted to test that theory. Ordered new glass fuel filters for before the boosters and took the P side fuel pump back off.

So, I ran with 1 booster on S and stock on P motor.

Ran today in lake with 69 degree temps (cool out) Ran 5k at 66 (fastest so far with these labbed props)

Everything was ok for about an hour, then as I was headed back, I tried to run WOT again and maxed at 4500. Stopped, lifted hatch to look at glass filter and clear. Took off again and ran up to 5k, turned around and only 4500 again with both engines acting the same. Stopped to try to cool off and try again and still 4500 max...

Wth?? Would water in fuel do this? Odd that I drained both filters and it ran good for and hour and then started acting up again. Thought I was haveing issues before and had checked fuel pressure on P a month ago and 38 at idle and around 2k while running on hose.

I will get some new fuel filters and try again and I put another 50 gallons of fuel in. May put some heet or seafoam to treat rest of tank.

Its got to be fuel right?? runs perfect at start up, idle, everything below 4500 rpms. Both engines are doing it. Fuel? or could fuel pumps be wore out?

runs well except wot..

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Do they have seperate tank pick ups ?

Check the fuel pressure at wide open throttle.

Yes, have 3 bungs. 1 pickup for each engine and 1 for return fuel. they are all right next to each other.

I was going to test fuel pressure at WOT, but was by my self... But, it ran like a spotted ape for about an hour, full power all the way to 5k, then after about an hour, next time I tried to go WOT, maxed at 4500..

4psi for fuel injected MPI engines? Is that right?

They are set 7psi low pressure booster pumps. The fuel injector pumps in the cool fuel is the high pressure side. 4psi is continuous at 72gph flow. All they do is pump fuel from tank to filter head and high pressure pumps pulls from there to injectors.

I thought they might be a bit low, but from what I have read, they only burn about 65 gph at WOT so they should be good,

But, that was why I pulled one of them off the P engine to see if it was restricting fuel even though it freeflow fuel through as well and run at idle and just off idle.

Ok, it's the lift pump.
Thanks

Yep

Update: Was questioned about whether coils were replaced when new long blocks added. Well, I went through my paper work and they did not change the coils? Are these symptoms of coils going bad? Get hot and cant carry wot spark?

Maybe fuel pressure regulators? I had a odd wot RPM issue that would come and go, fuel pressure would drop to zero after I cycled the pump, but you have a return so that would have to be shut off to test.