1957 Evinrude Pressurized Gas Tank Leaking Fuel

[BSDenning]

I've got a pressurized gas tank that came with a 1957 Evinrude (6 gallon capacity). I've had the tank for about 3 years and have had no problem with it at all. A few weeks ago I noticed that fuel seemed to be leaking out of the tank while it was stored in the shed. The shed gets pretty hot during the afternoon and the tank seemed to only leak during the hottest part of the day. I had never replaced anything on the tank, so I decided the time had come to rebuild the tank. I ordered a rebuild kit and new double line fuel line from Laing's Outboards. I installed the new fuel line, the new connector o-rings, and the main gasket on the tank. I did not replace the fuel pump diaphragm, because the one that was in the tank had some type of round metal disk that seemed to be riveted to the diaphragm. The diaphragm that came with my rebuild kit did not have any type of metal disk attached to it. So, I took the pump apart and checked everything. I checked the diaphragm and it seemed to be in good condition. I checked the pressure relief valve and it appeared to be in good condition and was not stuck or anything like that. So, I put it all back together and tested it out. Everything seems to work good with it. The fuel pump pumped fuel. The tank held pressure. So, I thought I had fixed the problem.

Now, the bad news. Today, I found that my tank, which had about 3 gallons of fuel in it, leaked every bit of the fuel out in my shed. So, the problem is not fixed. Any ideas on where this fuel could be leaking from? The only thing I can think of is perhaps I need to replace the diaphragm, but can I replace it without using the metal disk, or do I need to drill the metal disk off the old diaphragm and rivet it to the new one? Thanks in advance for any and all ideas.

-Bret

 

[F_R]

Re: 1957 Evinrude Pressurized Gas Tank Leaking Fuel

That particular tank was made only one year, 1957. The diaphragm is part number 377327, comes with supports assembled. Still available from any Evinrude dealer.

1958 tanks had a different diaphragm, button, and a separate lower support. As far as I know, you can update them (?).

305715 diaphragm
305714 support
305713 button.

 

[BSDenning]

Re: 1957 Evinrude Pressurized Gas Tank Leaking Fuel

That particular tank was made only one year, 1957. The diaphragm is part number 377327, comes with supports assembled. Still available from any Evinrude dealer.

1958 tanks had a different diaphragm, button, and a separate lower support. As far as I know, you can update them (?).

305715 diaphragm
305714 support
305713 button.

Thanks F_R! I really appreciate the help that you and many others give on this site! There's no way that I would have been able to learn as much as I have about these old motors without the help from you fine folks. Thank you.

 

[1stgenbird]

Re: 1957 Evinrude Pressurized Gas Tank Leaking Fuel

It's good that you found the leak. When I store my pressurized tank, I unscrew the tank filler cap a bit so in the hot weather the pressure doesn't build up.

 

[BSDenning]

Re: 1957 Evinrude Pressurized Gas Tank Leaking Fuel

It's good that you found the leak. When I store my pressurized tank, I unscrew the tank filler cap a bit so in the hot weather the pressure doesn't build up.

Yeah, I think I may start doing that. By the way, I haven't found the leak yet. I'm just hoping that if I get the correct diaphragm, that will fix it.

 

[rickman4488]

Re: 1957 Evinrude Pressurized Gas Tank Leaking Fuel

I just bought a 1957 18hp Johnson seahorse electric start outboard. The motor works great but the pressure tanks are leaking where you push the button to pressurize the tank. How do I stop these tanks from leaking. Is there parts and where do I get them? Thanks.