Looking for some ideas here as I've been trying to get my boat running right all summer and with only 7 days till we leave for the shootout I'm in a little bit of a time crunch.
boat is a 1992 Challenger with a 525hp 496 roller motor.
-Boat was running great first time we took it out and half way through that trip we broke a valve spring. We didn't know it was a valve spring and thought it was fuel related since it ran great up to 3000 rpm. We had the carb rebuilt (barry grant 950cfm) and a power valve was broken. thought that might fix our problem but it didn't. boat did idle better though.
-Replaced all the ignition parts (coil, plugs, wires, cap, rotor, pickup) and no change.
-Pulled valve covers and found the broken valve spring, replaced all valve springs and boat ran great for about 5 min then died due to a plugged secondary 40micron filter before the pump. (got some bad gas earlier in the year and I'm guessing that was the cause) Cleaned that out and started the boat in the driveway and it ran like a brand new boat, started better, idled better ect.
-Took it out a couple days later and it ran awesome, for about 20 min then progressively got worse to the point is was hard to keep running 20 min later putting it on the trailer.

My first thought is the fuel filter again, but if that's not it I'm looking for some things to check that I might have overlooked. any help or ideas would be greatly appreciated! I don't want to drive around in my truck or be a boat slut for the shootout lol

I'd start by removing the fuel water separator and pouring it into a jar to see what the gas looks like. Then install a new one .

Dumped the filter out last night and had some debris come out, not a ton though, took the element out of the 40 micron filter before the pump put a new mercury spin on filter on and boat fired up and ran great in the driveway.
I've got a new element for the 40micron filter that will be here today, and I'm guessing that's my problem. Only other thing I can think of is the fuel pump may be getting hot after running for awhile and not pumping as much fuel as it needs to? Will a fuel pump do that or are they all or nothing? has a holley blue electric pump that is as old as the boat (1992 230hrs) i'll post a pic of the fuel system here in a minute...

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Pump could be the issue, do you have a pressure Guage to verify output ? Best bet is order one , and take it out and run it with the new filters , if problem persists you'll have a pump before the run, or if all is good, a spare.lol

Most pump companies suggest a more micron (less filtering) filter before the pump. usually 80-100 micron and many are cleanable / re usable stainless steel.

Check with Holley.

But yeh, as long as you keep pulling upcrap, the likely hood for a clogged filter is greater.


I ave a portable electric fuel pump wih many feet of rubber line on both ends that also has a filter I use to pull out fuel, it filters it of course, and I then burn it in my truck when not loaded or trailering. The toy then get's the good fuel.

Ordered a fuel pressure gauge and new pump this morning for that exact reason. Thanks!

Hopefully all will go good for you this weekend!

i would not use that holley pump.their are much better pumps now that will work much better.

I had a terrible time with Holley electric pumps on my boat. I was able to go back to mechanical and lived happily ever since.