Fuel/water separator, can I drill and tap?
 

I've got a stock fuel water separator for a 454 mag engine. That is the only part in my fuel system that is 1/4' NPT fitting. everything else even my Holley fuel pumps are 3/8 NPT. Is there any reason I can't drill and tap them to 3/8"? Looks like there is plenty of material to do it. I am moving from 525 or so hp to 650.

That is what I did - I drilled and tapped it and made sure that all of the passages were at least 3/8. I am running 650 HP

the stock filter mount still has the cork in it. take the mount off and turn it upside down - then look where that fuel comes thru where the inlet you are going to drill - it still is about the size you can only stick a Q -tip in. very small diameter. Total waste of time drilling the stock mount to fit a 3/8 barb fitting into, the cork is after that.

move on and buy a billet one or an one that still does not have a cork in the system meaning the portion where the incoming fuel is going into the filter that has a bigger diameter than what the stock mount offers..

done a few of them too.Just be careful,you can break the housing if you tap to deep and fast.

It's been a while but I believe it was easy to drill the passages to at least 3/8 inch. I don't have any problem with fuel flow.

forgot the other cork in the fuel system is the L fuel fitting sitting on top of your gas tank that your fuel line attaches to. One it has a restrictive anti siphon valve in, plus make sure your fuel pick up is clean and not cracked or bent and then the fitting is L shape - L shape fitting are not the best flowing of liquids nor is the anti valve. Just saying if your app still has all the stock fuel configuration.

Hey Guys, nothing wrong with doing that but I know that a lot of filter mfgs. have different flow rates passing through the filters, has something to do with how many microns the filter will flow......You have to be very careful to get the right flow rate or you will starve that big engine .......Don't buy junk and check the flow rates ..

don't forget you still need a enough meat for a TRUE 3/8 drill bit on the outlet side of the mount drilled all the way thru as well. Some of the OEM mounts had more meat internally in certain years that could be drilled & tapped but some years not enough especially mostly on the outlet side to be drilled all the way thru and tapped far enough without cracking.

As for the inlet side drilling a 3 / 8 bit all the thru could be very hard without getting into the base of the filter mount.. I am telling you for a fact. Been there, seen it & measure it & replaced with new

I do sell an aftermarket mount thats even slightly a tad bigger than 3/8's hole internally all the way thru both inlet sides and outlet sides, exact replacement of the stock app. Externally looks the same. Its works for V- 6 all the way up to whatever. I do not recommend it for 1/2 inch fuel apps because their not enough meat to drill that size out.

Let me know how yours works out with the 3 / 8 drill bit internally NOT going into the filter base itself on the inlet side because that hole is not centered in that portion, it is almost drilled into the base as it sits. plus the bigger hole & tapped with enough depth. I am talking about the 1/4 size here and the internal portion of that tiny hole on the inlet side plus for the portion for the bigger hole to fit a 3/8 barb depth then tapped correctly ..

. The new filter mounts that I have and even slightly bigger than 3/8 holes both inlet & outlet sides all the way thru are no more than 50 bucks.

While you can drill and tap the stock 1/4" mount that you have. Sierra offers both a SS and an aluminum version that is already 3/8". It looks identical to the one you have and will mount up exactly the same. I don't have the numbers in front of me but I think the SS version is #18-7776. It is around $50.
Eddie

If I never gas up at the dock, do I really need a fuel/water sep? My truck seems to manage just fine and if I can remove it from the bilge I'd like to.

I had an issue last year. I always fill up on land. I had 3/4 of a tank, my boat was stored in an un-heated garage. I would heat it for a weekend here and there to work in the garage. The temperature swing made my tank sweat. Had a whole bunch of water/phase separation occur. Had to pump all the fuel out and refill with fresh. What a nightmare. Took me all summer of swapping filters, pumps, lines, and carbs to figure out what actually happened. My point is moisture doesn't always come from the fuel itself.

O-ring or seal dry rotted out or cracked or missing to seal the gas cap is another water source that seeps down in your fuel fill into your gas tank from waves, rain, or just plain old washing your boat. Storing your boat in humid conditions can sweat condensation of the top of your fuel tanks.

The source of fuel does not matter and E-0 Non ethanol fuel did not fair any better when water contaminated it than E-10. If you think water in the fuel is only a current issue because of E-10 this is totally not true as marine engines had fuel water separating filters for the past 35 years as water entering the fuel can take place however....

That is correct about the Stainless steel filter mount with 3/8 holes from Sierra 18-7776 as the same one I sell but dealer cost is around 45 bucks it retails for around 72 bucks. The other one is a kit with the black filter mount comes with 2 - 3/8 plug fittings and the 10 micron filter for 50 retail.

BUP you mailbox is full. How do I order from you?

Thanks guys. I suppose Ill set it up like sep ---> pump ---> post filter ---> rail

Sorry hit my email make sure you put a title on it so I know who it's from.

[email protected]

Mercury recently came out with this. I am not sure of the inlet size, it looks like the same old bracket to me. And a stainless bracket sure sounds like a good idea. But the filter element looks pretty good.

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On the Diamond Marine website they have a 3/8" fuel filter kit listed under Engine parts-> Fuel system Parts...no pricing!

http://diamondmarine.com/

Mark, I run these. 1/2 ports and wix 33405 separators. 22 bucks per filter base here, same base the marine perf vendors sell for 45 each. The filters here are 12 bucks each, at the marine perf vendors, almost 30 bucks each.

http://www.fleetfilter.com/filter/wi...ses/24770.html

http://www.fleetfilter.com/mm5/merch...Category_Code=

thanks Joe

One last tip guys, You might want to look at Racor water separating filters with an alum. canister that screws on to the bottom of their filters :It has a nut on the bottom so you can drain the water accumulation out and then close it back up without having to remove the filter... It screws right on to the merc brackets and they also offer different fuel flow rates in their filters ......Two complete units cost in the $120 range Jim

Those are good prices for the wix filter and the mount that MT posted - will have to say it is wise to take a inspection mirror or take the mount completely off for inspection of aluminum oxide it is a form of corrosion more so now with the current fuels. A couple of things with this from of corrosion is it is a white powdery substance - one it jacks up fuel injectors, or passages in the carb, Second is it even forms on the sealing surface in which makes for a poor seal causing air into the fuel system causing lean conditions.

If anyone is interested I found my pics of the older models of the OEM fuel filter mounts to better show you about wasting your time drilling them out plus drilling for a 3/8 NPT fitting- it gets pretty thin for the depth needed. If you want I can send them to someone and they can post the pics up here. If not no big deal and less time n& work for me to.

I have the Sierra SS 3/8" mount. It is very nice and a good price. I drilled the internal passages on mine to the same ID as -10 fuel line. Was real easy. I also plumbed it with 3/8 pipe thread Stainless steel fittings which I also drilled out to -10 size.

I've seen that white substance in some marine carbs I've had apart. Could it be from the aluminum fuel tanks as well?

Joe 99 % of rec boats especially currently have plastic tanks and it is very common with aluminum oxide formation.

I have so many pics of this because I test fuel injectors & clean them so I have my dealer base make sure everything in the fuel system is spotless 100 % because the injectors had all this oxide debris in them time and time again.

hence clean injectors at engine start up collects all the white powdery all over again. I show the pics of parts that have formation of aluminum oxide and most miss under the filter mount. It is on the outlet side past the filter on its way to the carb or injectors.

Mechanical fuel pumps are bad with aluminum oxide internally. Have those pics to.

Gotcha. Most boats I've been around, Fountains, cigs, scarabs, etc, all have had aluminum fuel tanks. Are the new offshore boats using plastic tanks these days?

I am in fresh water and 95 % boat apps I work on are fresh water.

I know a lot of it has to do with E-10 fuel and IMO this is part of the problem as well. The quality of the metal & the process of these parts are made/ Also barb fittings turn green and the corrosion formation on them that passes thru also.

EPA is going to make all builders use these new tanks and a lot of fuel tank parts as well like demand valves and carbon canisters - all cat engines boats have this already installed. the new plastic tanks are rated at low permeation and have liner coated to them. I have installed a lot of stuff already. The fuel lines all have change to meet EPA low permeation in which all started in 2010.

Even the fuel fills are different now, It is coming to the high performance end. The CAT system is still up in the air for over 500 hp. It all has to do with carbon credits from the marine engine manufacturers. Meaning that they have so many that meet or beat the emission control that they can still make non CAT engines meaning the High Performance engines no CATS.

Outboards are next for the CAT system. It has been in testing for 5 years that I know of. The failure of CAT is the holding part of it back among other issues.

That is extremely depressing! ^^^^^^^^^

Here is the new set up and Attwood supplies a lot of the rec boat builders. link below and watch the videos. All CAT engine builders have to meet this set up. Outboard boats have changed as well.

http://www.attwoodmarine.com/store/c.../system-design

what could possibly go wrong here....thunder have seen the same stuff in carbs I've had apart as well...seems has to come from the E10 and started showing up when that did as well...

You should see the mechanical fuel pumps that the 3.0 - 4 bangers use from Volvo and Merc. Carb apps. And I am talking about almost brand new boats / engines - 2 year old and back. See in those apps there is a small filter inside the bottom of the mech fuel pump that's need to be changed once a year and of course no doesn't do it, so the longer they sit the worse the internals of the mech fuel pump gets plus the filter is just completely bad and all sucked inward in which causes a restriction as well for fuel flow..

Some mech fuel pumps internally end up looking like that baby powder was poured into them. What happens is the boat will NOT start anymore - the main reason is the carb can not get any fuel because the inlet screen fuel filter in the inlet fitting to carb is so impacted with this aluminum oxide, blocking any fuel flow..

What really happens is the E-10 starts etching the internals of the fuel systems metals, then over time water / condensation builds in the gas tank or a water source finds it way in into the fuel tank. next the ethanol falls out of the fuel, mixes with the water and forms acids. (phase separation) These acids attack todays metals like crazy. With aluminum it forms aluminum oxide a from of a corrosion the white powdery substance. Very common and green corrosion on brass fuel parts. This aluminum oxide formation is very common as well on the internals underside of the fuel water sep filter MOUNT. Even on the sealing portion aluminum oxide will form for the spin on fuel filter. Like I said it can cause lean fuel conditions because of air seeping into the fuel flow while running. Not uncommon, I see it a lot.

One day I will learn how to post pics up here - you would be amazed at some of the stuff that I have found and taken pics of. Anyways just some added info.

I've danced the ethanol corrosion / gooey stuff dance with my last boat.
I started using a fuel stabilizer but also just started to drain and remove the carb and put it in the house for the winter storage season.

A really good quality 2 stroke motor oil mixed in with the gas and ran thru the engine for a good 15 to 30 mins for any length of lay ups really does help. we have been using 50 to 1 all the way thru 80 to 1 so far have not come up any conclusions. 80 to 1 less spark plug deposits. Merc spec is 10 to 1 and that is just too much oil. 496 fouls spark plugs out like crazy at those ratios. Also for CAT engines too much oil that can contaminant the cat sub strake IMO. Volvo recommends a 50 to 1. We went to that many years ago even before they recommended.

Yep, going to pull my tank pickup out and replace it. Do these commonly present an issue to remove? It has been in there for 30 years. kind of worried about the aluminum threads galling on my when I try to screw it out. I don't exactly feel comfortable applying heat to this area.

Is a good flowing replacement fuel tank pickup commonly a custom fabricated item, or does someone make one that fits most tanks and can be purchased?

I've never run into one that we couldn't get out. Sometime they are in there pretty tight though. On some of the tighter ones, we use a crow's foot with an extension so that we can get above the floor. Then you can put a long ratchet on it and get down. It's usually tough to get any leverage on it when working under the floor.

I've never been able to find a pickup that I really like, so we just make our own. I use .500 SS tubing and TIG weld it to a SS 90* fitting. Most all tanks are 3/8" NPT. We use a 3/8" NPT x #10 90* fitting. We bore out the 3/8" end of the fitting so that the OD is the same as the #10 side. Then we weld in the tubing. That way, you have 1/2" all the way through. I'm not crazy about having to use a 90* fitting, but most boats don't have the clearance between the floor and the top of the tank to use a straight fitting and a 90* hose end. Not to mention, I've used that pickup to support over 1000 hp.
Eddie

MT, do you know if they make a shorter version of that fuel/water filter that still has the drain on it? I like the idea of the drain, but don't have enough room for a filter that size in the current location. Thanks for the link!

Thanks for the reply, Eddie. Are there any concerns with galvanic corrosion occurring with the dissimilar metals (SS versus the aluminum tank)?

Haven't seen any as of yet. I've been making and installing those pickups for about 15 years now and haven't gotten one back yet. I'll probably get one tomorrow now. lol

LOL - and I would be the guy who's gas tank turns into a battery and has problems. :)

Yes seen dissimilar metals cause corrosion on aluminum fuel tanks and also seen pin holes in them as well.

There is a lot more to it than just the pick up causing it. Terminal connections - copper, tinned metal, or whatever, then the bolts and nuts used from S.S. to low grade metal, also standing water that can sit on the fuel tank or below it. Also brass fitting connections and hose clamp metals attached among some of the welding material and more.