replaced fuel pump - leaking at carb

[lrlima]

1993 4.3 OMC with Holley 2bl carb

Just replaced the fuel pump and all fuel lines. For the fuel pump to carb line, i used the factory pre-formed metal one. (The fuel line has the brass threaded inserts already connected to each end).

The end that comes out of the fuel pump fits perfectly. The other end that goes into the carb required another brass fitting to take it up to the size that fits the carb, so I found the right size at napa. I didnt use any sealant on any of these fittings and after starting and looking for leaks, I noticed some "sweating" or slight leaking of fuel the fitting that goes into the carb.

My question - should I seal that one fitting that goes into the carb with something, o-ring, brass washer? I have searched other posts and know that I dont use tape...and fuel connections dont require a sealant...

Im basically replacing a lot of stuff that that previous owener did incorrectly and want to connect everything right, and avoid going *boom*...

 

[JustJason]

Re: replaced fuel pump - leaking at carb

I'm not an omc guy but if you have a metal line thats leaking it's usually only 1 of a couple of things.

1. not torqued enough
2. you have an incorrect or damaged/dirty flare on the end
3. you have an incorrect or damaged/dirty flare on the recieving end

i'd pull it out and look at the end that goes into the carb and look inside the fitting that's in the carb too.
good luck

 

[lrlima]

Re: replaced fuel pump - leaking at carb

thanks for the replay. I could probably tourqe the fitting that goes into the carb more, however i had it pretty snug initially. I felt like if i kept tightening it may crack the casing...so it sounds like no sealant / oring is needed.

 

[Haut Medoc]

Re: replaced fuel pump - leaking at carb

thanks for the replay. I could probably tourqe the fitting that goes into the carb more, however i had it pretty snug initially. I felt like if i kept tightening it may crack the casing...so it sounds like no sealant / oring is needed.

Nope, no sealant or orings, it is a compression fitting.....
Look for 1 of Capn Jason's reasons for the leak.....

 

[bomar76]

Re: replaced fuel pump - leaking at carb

Cross threading is a common issue......

 

[JustJason]

Re: replaced fuel pump - leaking at carb

thanks for the replay. I could probably tourqe the fitting that goes into the carb more, however i had it pretty snug initially. I felt like if i kept tightening it may crack the casing...so it sounds like no sealant

So does the fuel line go directly into the carb itself? or is there a fitting (a seat) that the fuel line connects into? isolate where the fuel is leaking first. Blowing some talcum powder around the area may help you find it. Maybe the carb is already cracked and thats the problem. let us know what you find.

 

[lrlima]

Re: replaced fuel pump - leaking at carb

thanks for all the replies. CaptJason, The fuel line does not fit directly into the carb, but needs the seat like you mentioned. Thats where it is leaking from. Not the connection from the fuel line to the seat. But rather the seat to the carb. I was also thinking about the cracked casing, but it did not leak with the previous fuel line that was attached (i replaced it with the factory metal one)

I am going to tighten another 1/2 turn or so to see if that helps like you originally said.

Im just a little paranoid cause im taking or son (10 months old) for the first time out on the water...so im fixing a lot of things that I felt the repvious owner did half way.

 

[Coors]

Re: replaced fuel pump - leaking at carb

I seem to remember, that some holleys used a paper gasket on the brass fitting that screwed to the carb.
Is the carb, and fitting both flat where the mate? Then a gasket goes there.

 

[lrlima]

Re: replaced fuel pump - leaking at carb

Coors - yup, its flat where they mate together. It would make sense for something to go there, thats the feeling I got that led me to posting. the guy before me had tape around the fitting which may have prevented any leaking previosly. ALso led to my carb rebuild...

 

[capecodder116]

Re: replaced fuel pump - leaking at carb

I'd go to an OMC dealer and check with them. It may just be as simple as needing a thin paper type gasket between the mating two surfaces.

 

[bomar76]

Re: replaced fuel pump - leaking at carb

I'd go to an OMC dealer and check with them. It may just be as simple as needing a thin paper type gasket between the mating two surfaces.

The OMC dealer would be between Kaiser dealership and the American Motors dealership.

 

[Maclin]

Re: replaced fuel pump - leaking at carb

With Holleys there is a thin metal gasket needed between the fuel bowl and the fuel inlet fitting. This is the large fitting that screws into the fuel bowl, the threads are nearly an inch in diameter. It houses the female flare fitting and threads that the male fitting on the fuel line screws into. This gasket HAS to be metal, way too much clamping and twisting force for a paper gasket to stay together.

If you have an adapter between there and the fuel line there are no more gaskets but you do have to tighten the flare fittings to what may seem to be an uncomfortable level. Tighten the adapter alone into the fuel bowl fitting first if you are using one, be sure to back up the wrench on the adapter with a wrench on the large fitting at the fuel bowl. Tighten the fuel line fitting into the adapter next, backing up with a wrench on the adapter.

 

[lrlima]

Re: replaced fuel pump - leaking at carb

good one, i'll head there after i finish tinkering on my delorean.

seriously, in looking at the old seat that i removed, it looks like something had to go there. i'll get some time tonight to mess with it.

 

[sarantis]

Re: replaced fuel pump - leaking at carb

"Im just a little paranoid cause im taking or son (10 months old) for the first time out on the water...so im fixing a lot of things that I felt the repvious owner did half way"
I think you' re really paranoid if you take your son onboard.It is a baby!There are many dangers on the water exept an engine failure.

 

[sarantis]

Re: replaced fuel pump - leaking at carb

I'm sorry ,i'm not superstitious but i just noticed my previous reply was the thirteenth!Better wait some months more.I 've a 14months old daughter and i can understand your impatience. Personally i 'll let her in when she 'll be able to float on the water with a life jacket,i hope the coming summer.

 

[Coors]

Re: replaced fuel pump - leaking at carb

Advance auto or anybody has that washer in help section. Not always metal.

 

[JustJason]

Re: replaced fuel pump - leaking at carb

id take the seat out and bring it someplace... if they don't have a listing (and an advance auto or anyplace like that won't) you can match it up to something... most places have assortment type boxes. get something a tick smaller than the threads and you should be ok. try and get something copper instead of plastic or fiber if you can.

 

[lrlima]

Re: replaced fuel pump - leaking at carb

just wanted to follow up on this in case anyone else has the same problem...Maclin and Capt jason were right. It takes a metal gasket. I found it in my tool bag and must have put it in there when i took everything apart. Thats what happens when you wait a week to put everything back together after ripping it apart. Its pretty thin about the width of the threads...tightened everything up and all is good. Thanks again for the replies.

 

[Maclin]

Re: replaced fuel pump - leaking at carb

Good deal! thanks for posting back....