fuel hose size and fittings

[irtrimble]

Don:
I'm planning to install a Racor filter. What size fittings should I get for the input and output lines? I know that the threaded fittings are 1/4 inch NPT, but don't know the diameter of the fitting into the fuel pump.

[CalebD]

I spoke to Ken in parts recently who assured me that the mechanical fuel pump on my engine needed a 1/8" NPT 5/16" barb (I wrote this down). The Racor filter may have 1/4" NPT but you would still use a 5/16" barb for the standard fuel hose with hose clamps.

There is another type of fitting that can be used in the fuel lines called Fastenal. These came up in another thread I started on a similar subject: http://www.moyermarine.com/forums/showthread.php?t=5768

[jpian0923]

No offense to CalebD but I would steer clear of Fastenal for fuel line. To me, it's not safe enough, it's not easy enough to service, and it's not easy enough to install without much experience.

Also, I think they advertise it for air lines and low pressure oil lubrication lines. To me, not safe for fuel.

Just a safety thing. I might be wrong but, it's not on my boat anymore.

[CalebD]

Jim,

I don't endorse using Fastenal fittings for the fuel lines. I only recently discovered that I have these fittings on my engine and I am in the process of replacing them with traditional hose barbs. I just prefer to have all my engine hose plumbing connections of one type using hose barbs, hose and hose clamps as the cooling water side of my engine is set up.

YMMV

[dvd]

My fuel barbs are 5/16

dvd

[smosher]

The fuel barbs size must match the size of your fuel line and 5/16 is usually what is installed.


Steve

[ILikeRust]

I discovered that the P.O. of mine had installed 3/8" fuel line - but the fittings are 5/16". He had double clamps on everything, cranked down tight. So there were no leaks, but I'm wondering if he kept wondering why he had to go to such lengths to keep it from leaking...

I replaced it with 5/16", which fits much better - since that's what size all the fittings are!

[smosher]

I redid all of my hoses and fittings when I put in a racor filter, The engine would shutdown on occasion and took me awhile to figure it out. When I bought the fittings a 1/4 barb was mixed in the 5/16 barbs. When I was pulling all of the fuel hoses off, 1 came off very easily, unlike the others. That small size difference made a big difference in how sealed the connections were.

Steve

[Bold Rascal]

What, if any type of sealing are folks using on those threaded fitting connections? I'll be using brass fittings, My rigid fuel line from the tank to the Racor filter is copper with threaded flared fittings.

[ndutton]

Originally Posted by Bold Rascal

What, if any type of sealing are folks using on those threaded fitting connections? I'll be using brass fittings, My rigid fuel line from the tank to the Racor filter is copper with threaded flared fittings.

If you mean the Fastenal type flared fittings, no sealant is used. The 45 degree machined surfaces mate perfectly when made up wrench-tight. Same thing with flared copper.

If you're referring to pipe threads, I prefer Permatex #2 for fuel system fittings.

[Bold Rascal]

Not sure if the flared fittings are "Fastenal" but appreciatte the advice. Was mainly concerned regarding the threaded barbed fittings going into my new Racor and Facet pump.

[ndutton]

Originally Posted by Bold Rascal

Was mainly concerned regarding the threaded barbed fittings going into my new Racor and Facet pump.

Yeah, those are pipe threads and require sealant. As said, Permatex #2.