Fuel System Fittings
 

What are you guys using on the 3/8 fittings to seal the threads in the fuel system?

I bought the new boat about a month ago and it had the holley red pump, the fuel pressure wasn't high enough, and the red pump wasn't sufficient enough on flow. So I got a whole new system with the Holley blue pump and regulator. Installed the system using all -8 AN lines and fittings, and -8 AN to 3/8 for the pump, regulator, and filter. Well my 3/8 are leaking a little at the regulator in and out. I used liquid thread sealant, and you can see little flakes of it like the fuel is eating it. A buddy of mine did both his motors about 2 months ago, and he said it leaked everywhere that liquid thread sealant was used. It works great for water fittings, and oil fittings but seems like it can't stand up to fuel. So my question is what are you guys using to keep these sealed up from leaking? Thanks for the help in advance

I use teflon tape on NPT fittings, most of my aeromotive fittings are now strait threads with a O-ring seal

i use leak lock,best thread sealer i have ever found.

Hey Mike where did you get your leak lock from? looks like walmart carries it lol

On a side note: make sure that the fuel pumps are no higher than the gas tank. Holley pumps HATE to lift fuel. I just went through the same thing with my Holley red pump - 3 PSI at the carb because it was mounted about 12" above the gas tank.

icdedppl got me a ton of it for me from his supply house.he uses it in his hvac business.do a googel search leak lok

i dont know what engine you have in the boat but i do know that the holley blue pumps are junk.id think about switching to aeromotive when the holley craps out and it will be soon.

Yea, the fuel pump is mounted right where the mechanical pump was, in my set up it is the best place for it. The problem with the red pump is its only rated to support 440hp, which is why I just replaced it. My fuel pressure is good to go now with the blue pump and regulator. Blue pump is in the exact same spot the red pump was, and I had zero problems on first start up, it started right up no problem. I have it set at 7psi at idle, and it only drops about .5psi at WOT. I think I am going to adjust the pressure down a little actually to about 6-6.5psi at idle so I am 5.5-6psi at WOT.

I have a completely stock 525sc

I've been using permatex #2 thread sealant since i was just about a teenager.

That was about 1,021 years ago. Plus or minus a few years. I've lost count.

I think he would be better off switching it now rather than having to get towed in. Minus well get rid of the junk holley regulator also.

You can use liquid Teflon but you have to get the good stuff it's $20 for a tiny tube. I use yellow gas line Teflon tape.

Lol, that stuff cracks me up. I work for a pretty big gas company and we use the white stuff.

I also use it on my fuel fittings.

The red pump that was on the boat was on there for 2 seasons and ran the exact same the day I took it off as the day it was put on. I just put the blue pump on last week, and I know several people running this exact same set up with great success. I am not saying parts don't fail as I know people have had them fail on them, nor am I saying the blue pump is the best thing out there, but its not going anywhere for now. I know a guy that has an aeromotive which has been in the boat for just this season, and looks like its been sitting at the bottom of a swamp for 20 years. No part is perfect

Why would you use an electric pump on a completely stock 525sc mercury engine?

It had an electric pump on it when I bought the boat. I am sure they went with an electric set up instead of buying a new sea water pump or rebuilding it. Its a guess, as that is what alot of people do when the seals blow out of the sea water pump.

I had a similar issue with the NPT ports on a Mallory Marine EFI fuel pump. Hylomar finally stopped the leaks, the only drawback is the price.

I never understood that. Some guys have a proven setup that hundreds or thousands of others are running with no issues, on an expensive engine like the 525sc was in its day, but wanna install the autozone high performance special fuel pump. Theres tens of thousands of mercury engines out there running the sea pump/fuel pump deal since about 1991.

Maybe thats why in the past month we've had about 30 threads with "fuel supply issues" and 29 of them start with " i installed some aftermarket electric fuel pumps".

No way in the world would I ditch the mechanical merc pump in favor of a holley electric, on a 525sc engine.

Look man This thread has zero to do with the fuel pump I'm running, it was simply asking what thread sealant guys use on there fuel system cause my fittings in my regulator are leaking slightly(used permatex liquid thread sealant). I read a lot of your posts and consider you to be very knowledgeable, but I am not a beginner at this either, I don't know everything, I know a little about a little, and always learning. I wouldn't take a perfectly good mechanical pump off to go electric either, as the mechanical pumps are plenty sufficient. I don't know why the electric pump was put on. The fuel pressure was on the low side when I bought the boat, so I made the necessary corrections to make it right. Mechanical pumps fail too. The Holley Blue pump is equivalent to the stock merc mechanical pumps when it comes to GPH. With holding 6.5psi of pressure at WOT I am not having a fuel supply problem.

guess he told you mild.!!!!!!!!!!!!!!!!i recomend he buy a good tow rope,LOL.

How much power did you gain from installing the electric pump?

:offtopic::chill-pill:

I didn't do it to gain power, i noticed my fuel pressure was on the low side, and I like my stuff to be where it's suppose to be. It provided zero performance gain, and didn't expect it to. I feel that your question was a smart ass question as YOU know that fuel pressure doesn't have a performance gain in a carb application. I was told by several that it would be fine. It I just didn't like what I was seeing. I just talked to Bob today about doing a roller set up so more then likely I will have to change the pump before next year anyway.

I apologize. Wasn't trying to insult your mechanical abilities. Just trying to make my point that the holley pumps were notorious for failing , the the regulators weren't much better. Besides the pump just quitting, the inconsistent fuel pressures were a pain.

Moving on. The 525 sc is a fun engine to upgrade. Going with one of bobs cams, possibly some flat top pistons if your rebuilding , is a nice bump in power. Watch those rear blower bearings for fuel contamination.

And 99 cent Teflon tape will work on your npt fittings. Just be sure not to get sloppy with the tape. Cleaning that crap out of the carb needle and seats is always a pain in the azz, not to mention burn up a piston or two.

The leak lock stuff mike tkach was talking about is some good stuff

look man,just trying to save you from the headache you are going to get from that blue pump but it,s clear that you dont need the advice you are being given.just fyi i rebuild the sea pumps and replace the seals&bearings for less than you paid for the blue pump&fittings.i sure hope the pump doesent decide to crap out while you and your family are on a boating vacation,good luck.:pray:

I understand that you guys are looking out, and this conversation has enlightened me that I should probably throw the red pump in the boat so if the pump does take a **** unexpectedly I can install the red pump to get me home. I am unfamiliar with what needs to be done to the sea pump to rebuild it, I was aware that it could be done though. I wanted to be on the water so just grabbed the Marine blue pump and straightened out some fittings and line routing so it was all -8 AN and done correctly. I was talking to a guy I met recently who works at jaws marine, and he clued me in that the Holley regulator has a casting line where they tap it and he always runs a tap through them before installing as he has several leak if he didn't and that always fixes them. So I am going to check that out and see if I can see the line he is referring to then run a tap through it and re seal it up.

Yes Bob has me very excited to do the conversion. As much as I want to go to the flat tops the motor was just freshens up along with the blower 150ish hours ago. With compression being 130 cold identical in every cylinder, great oil pressure, and no sign that the bottom end is in any kind if danger I just can't justify breaking it down, and Bob agreed. So the plan is to spec the cam with the idea that I will probably put an aluminum head on at a later date, and then rebuild time out the flat tops in and slide a new cam in for that set up. Problem with all that is the 177 won't make it through those mods, I think the stock blower will pretty much be done once the cam conversion is done, and will need to be upgraded to a 250 or 420 when putting heads on. Here is a good question for you, I have no extra clearance under my hatch (27ft fountain fever), and I don't want to cut my hatch, so the question is dimensionally, specifically height, is the 250 or 420?

I am trying to make the decision of whether to pick up this -2 imco this week, but I am getting mixed feedback. Stepped hull 95 27ft fever with a 5 1/2-5 3/4 X, just not sure if it's worth it. A guy said he picked up 3-5 on a 99 27 fever, and another guy said he got the same from a 98 29 fever. But have read people having negative effects speed and handling. But not sure the year they out them on.

Added info - I have been using Gasoila for over 30 years and 25 of those years has been in the marine business. At one time, most of the marine fuel app manufacturers especially on the outboard side for all fuel tank fittings would recommend using Gasoila. In the 60's and 70's this was a huge product for the motorcycle crowd.

www.gasoila.com - They have expanded their line of products as well.

Also Hylomar has very good products.

Almost any hardware store carries the yellow Teflon tape which is rated for gasoline contact.

I dont know the measurements off hand, although I do have them somewhere, buried. I had the 177, 250, and 420 blowers, on the same set of engines. If I were to do it over again, I would have skipped the 250 and went straight to the 420. The 420 is substantially taller than both of them though. Its close in size to an 8-71 dimensionally. Had them on the shelf next to each other this winter.

Thats what I was afraid of, it would only make sense for them to be bigger too. I have read alot of your posts on what you did with 525sc's and based on reading your info I planned to go to the 420 if I did a blower upgrade. But I am going to be limited to what i can fit under my hatch it looks like.

This year I kept getting small blue remnants of the leak lock in my carbs (seats) to the point i put them small stone filters in there.. for fuel fittings I think I`m going to stick with teflon tape.

My old line set up to the carb was a -8AN line to a Y in the middle of the valve cover, then fed both carbs, When I pulled that apart to put the dual feed set up on to clean it up a bit, mine had little tiny filters inside the feed ports on the carbs backed by a spring. I was advised to remove them since I have a 10 micron fuel filter and they weren't necessary or overkill. Sounds like thats something you are looking for, those little tiny screen filters

This is a pretty big" thread" for thread sealer. Loctite 567 seems to work for me, thicker than Permatex, the Permatex has to be kneaded together before using. If you want that ultimate seal use some Loctite 545.

Just my Nickel's Worth.

Watch out for adding other filters into your fuel system. They can cause lean conditions. Remember you want balance of filtering and fuel flow, there is a trade off. You can never have the greatest filter that filters 100% of the smallest materials because that will restrict fuel flow. Also too many added fuel filters will restrict fuel flow and is very hard on fuel pumps. Just saying

I didn't add any fuel filters, just replaced the one that was there with a better flowing filter, and removed those 2 little small screens that were in the feed ports of the carbs

I'm no expert on filters/flow rate etc, but my tech told me to run a filter ahead of the electric pump as the tolerances are so tight it doesn't take much tank sediment to cause havoc.

Yes some pumps say to run a pre filter of like 90 microns I think to get debri out that could damage the pump

That's correct about any filters coming out of the fuel tank before the electric fuel pump. They need to be 80 to 120 microns rated. That micron rating will not filter the small crap. Also electric fuel pumps hate to pull fuel - they do a whole better pushing fuel. If a filter before the fuel pump is too restrictive (finer micron rated filtering) it will shorten the life of it plus cause fuel flow restrictions.

The Mallory pump I believe is a specific pump that wants a pre pump filter as the littlest particles can kill it. I am pretty sure the holly has a built in screen to keep certain size debri out