I'm thinking about replacing the stock fuel water separators in my boat. I was shocked to see that they are only 1/4" npt, I believe when I discussed this with Dave Weseldyk (yes I know I really messed up his last name), he said the stock fuel system is good up to 600 hp. Has anyone else tested the limits of this this part? I should be in the 650-670 range, so I think I should at least think about replacing this. Also does anyone know what the flow limit is on the stock filter?

I would think 600hp is highly optimistic...but thats me, I did away with mine totally, also changed the tank outlet, was running little over 700 with a procharged setup(both carb and EFI) and never had a issue. But 1/4 I saw as well and thought even mild street stuff gets 3/8, I would think 450hp...

Yeah- I was really shocked last night when I pulled the old fitting and saw it was 1/4" npt. I was like WTH.

I used a housing meant for a diesel - less expensive than the "high performance" ones yet with the same larger ports - been to many years now, so I forget from where....

I ended up buying the Hardin Marine filter heads. With the filter, they were $89 ea. Not the cheapest option, but a lot cheaper than the Teagues which look like the same unit, and they didn't include the filters.

Perma-cool ? I've used them. 1/2" ports.

This is the filter I use and have room for on my stock 502 mpi mags. It fits the stock filter head and filters much better than the short 25 micron ones.

https://www.mercurymarine.com/en/us/...are/fuel-care/

https://www.fstperformance.com/rpm500

This is the one I'm using. Not cheap, but neither is my engine.

-12 O- ring ports

Hardin has filter heads that use the same filter for half the price. 1/2" NPT though so I think a bit smaller than -12 AN? The FST filter is a good performance filter. http://www.hardin-marine.com/p-74301...d-bracket.aspx

I pump my fuel thru the fuel/water seperator filter vs 'suck it' through. That increases the volume any filter and head will flow.