Fuel leak at carb

john33617 wrote: the problem is the steel line it keeps pressure on the fitting , JB weld the fitting in place , replace the steel line with a USCG hose , barb fittings on fuel pump and carb

Sorry John but you also are giving out bad advice. JB welding is not how a flare fitting is designed to work. You also need to review the USCG regs on plumbing on the high pressure side between the pump and carb. Barbed fittings?

Maybe you could get away with the hose if you drilled more holes in the choke plate?

When are we going to see some pictures of your boat and engine?

Oh brother, you have got to be kidding me...

There is more than one way to fix this problem and it is NOT high pressure fuel. The pump maybe puts out 14 psi, but I doubt it.

First of all, I always use clean fuel, so I've never seen rusted up fittings like you have posted pictures to. If you dump dirty fuel in the tank then I can certainly see your need to pull that filter every month or so.

I vaguely remember a fine mesh screen as described however at my last carb overhaul 3 years ago it was perfectly clean. I keep my fuel clean and that eliminates about 90% of problems in itself.

It's a poor design and it is a problem that keeps rearing it's ugly head. Buying new parts does not always solve the problem, and doing so doesn't permanently fix it either so I think you are giving bad advise as well.

JB Welding an adapter in place doesn't destroy a carburator either. a safety wire hole could be drilled to secure it too.

I have seen people struggle with this setup until the copper line gets over torgued and the flare cracks and then the boat is unusable. You just don't keep smoking it down tight with two wrenches. I have used the pipe thread sealant which I know you think is a pretty stupid idea, but it seals the threads (if the flair is leaking) and it also has a bonding agent in it that sets up so it doesn't loosen from vibration, yet it doesn't have the teflon tape shreds to foul the carburator.
I know, it's a really dumb idea...

If vibration is that bad, may want to check the prop shaft :)

I have owned my Nautique for 29 years and have yet to have the fitting vibrate loose. Guess I am the lucky one.

I would find the answer to my problems causing the leak and again fix it correctly instead of patching it with JB weld

Actually John is correct. The threads are weak because they are a poor fit, loose tolerance with the adapter. If the threads on the bowl were manufactured to the precision standard of connecting rod cap bolts then there probably wouldn't be an issue. There is no comparison here. And I certainly would not use a higher torque on the adapter just because it has fine threads.
SAE torques are higher for fine thread as these are generally manufactured as a high(er) strength fastener.
Course thread fasteners are generally low torque, although they can be purchased in grade 5 or grade 8, or can be purchased without a grade rating as well. No rocket science here.

Not all boats have the same engines and setups, some experience this and others don't. And I was not using the JB Weld to stop a leak, I used it to coat the threads so the fitting doesn't loosen.

skyhawkflyer wrote: Actually John is correct. The threads are weak because they are a poor fit, loose tolerance with the adapter. If the threads on the bowl were manufactured to the precision standard of connecting rod cap bolts then there probably wouldn't be an issue. No rocket science here.

What class fit are they? H2,H3,H4? Have you measured?

I could care less what class fit they are. Have you measured them? Let me know what you come up with.

John,
Thank's for the link. John's link That fishing site forum does have some smart people on it that know how to handle the fuel lines from the pump to the carb.

Here's a copy/paste:

"Quote:
Originally Posted by inetmug
Hey Guys,

I imagine the fuel line setup from the FP to the carb is supposed to be hard plumbed like in my old IO's. I hate to admit this but I just noticed the previous owner jury rigged it with standard CG fuel line to a barb fitting, most likely when they replaced the carb in '05. The line is not in danger of chaffing or near anything hot, but still it is not right I imagine.

What is the proper setup for this, and can a steel braided line be used? I am told yes. My local Holly speed shop has SS brained line with alunimum fittings but they could not comment on ethanol with the lines, and since they all pump high octane stuff they do not see ethanol."

Reply from Jimmy's marine service:
"personally,i would never use that set up-i realize the cg states it's ok,but it doesn't pass my test...
get the correct line to fit it-order it from the mfg of your engine.
i've ran into this alot as well,owner's some times lack tools,they use a regular openend wrench on the fittings,round them off,instead of using the correct flare nut wrench...the "pre shaped" lines are available from crusader,mercruiser and pcm...use a dab of grease on the line then,slide the nut over it,this will avoid the nut siezing to the line..."