Stock Fuel/Water separator hp limit
 

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. :)

I'm surprised over all the years you've been playing on the water and pulling engines etc you never noticed those little peanut size fittings. Brings up a good point though where performance engines really need to follow everything right back to the fuel pick ups in the tanks. Makes you wonder if that's part of the problem with fuel pressures dropping at WOT on some of the threads recently.

Stock is potentially a problem let alone a boat that is new to somebody that was owned by rig master. Just some valid points for repowering as well as general maintenance. Nobody likes those "wished I woulda" moments. Can be costly.

Perfect. All else fails purchase the filter and spin it on whatever remote mount you want. Adapters come in all sizes. Years ago I've used remote oil filters mounts with 12 AN fittings water/fuel seperator. I'd like to cut on of those filters down through the center after replacement.

Which one did you get mike?
Those vst filters appear to be very good. Would be kinda neat if we had a thread like the old oil filter thread that was extremely educating to say the least.


SB here you go. 53.00. https://www.summitracing.com/parts/prm-81794
The same one in a derale is 43.00

I noticed that a long time ago, and talked with Dave at Wesco Racing about it. He said up to 600 hp the stock fuel system is fine. However now I'm over 600 hp and I have 90 fittings all over the place. There has to be some major restrictions going on. Either way, everything from the tank to the carb is being replaced with -10 AN fittings and hoses. That is this weekends project, along with plumbing the water pressure relief valves.

FYI.......the FST filter is OE on all the big horsepower Mercury Racing engines. Yes, FST is expensive, but way less than if you buy it with the Mercury Racing label on it!

We have used these and there are multiple other fuel/water separators offered on Amazon. https://www.summitracing.com/parts/prm-81794/overview/

Thinking of buying a couple of these couldn't find the flow rate , any one have this imfo . Thanks

I just got one of these myself for my new build.

Wix 24770 filter base and Wix 33405 14 Micron large capacity Fuel/Water separator with drain. ~$50 720GPH setup
https://www.amazon.ca/Wix-24770-Filt.../dp/B000CSGT64
http://www.oreillyauto.com/site/c/de...2515&ppt=C0024

That is all correct

I never really gave this much of a thought but curious how you come up with it. I suppose testing with an electric pump before and after would give pretty quick results. I've just never tried it. Good point though. Only downfall I could see is potentially contaminating unfiltered pump?

Any more commentary on push vs. pull? I am pulling through now with a KE pump on the pulley set up. Loosing fuel pressure above half throttle. I would have though my setup would support 650HP. All -8 with sweeping bends from the tank to the carb.

I pull through the setup I mention earlier with Mallory 140 electrics. Filter below top of tank and pump below filter.

Didn't one of the engines I sold you come with a stock fuel / water separator?
I drilled and tapped that one for 3/8 inch NPT fittings. There is enough material to do that.

i recently rebuilt a set of hp500 efi engines that were bumped to 600 hp in 2009 and the engines showed no sign,s of fuel starvation.i would not use the stock filter/filter head combo with anything over 600 hp.