Pressure Tank Leaking

[outboardboy3]

I recently rebuilt this pressure tank for my 1957 Johnson 18hp, and it is leaking in some places. It is leaking around the plunger button, and around the fuel connector. I can have the fuel connector rebuilt, but am more worried about the other leak more. It also isn’t building up any pressure in the tank, when I take the cap off. Or when I disconnect the fuel connector. I appreciate any feedback.

---

Attachments:

[RICHARD A. WHITE]

My first guess would be the wrong fuel line, and then those clamps wont clamp properly…

http://www.richardsoutboardtools.com
classicomctools@gmail.com

[chris-p]

You need new o rings in your connector. Talk to Richard above about a tool for doing so.

You also need to rebuild the diaphragm in your tank. There is a way to seal them around the shaft of the button so that they don’t leak.

[outboardboy3]

I rebuilt the diaphragm and gaskets in my tank, so I don’t think it’s that. I will look into sealing that button.

[chris-p]

Well that is where you seal it, where the shaft punctures the diaphragm. You need to seal it before you install the washers.

[aquasonic]

What I don’t see in the picture is any evidence of sealant being used. Also, not sure if the washers are present under the flanged screws for the top casting. As Chris said, the diaphragm penetration needs to be sealed, but also the top gasket and top screws need sealant.

[frankr]

About that button leak: There are a few requirements.

1. The lower end of the push rod. They get corroded where the diaphragm support washer contacts the rod. The rod must be flat at that area (just above the threads).

2. The diaphragm support washers. They must be flat (except the outer rim, of course). And not rusted at the center hole area. That flat center area against the flat end of the push rod is where they meet and seal (with a dab of fuel-proof gasket sealant). And yes, they will deform a bit when you tighten the nut. That assures that they seal against the diaphragm material.

3. The push button knob: It is supposed to spin freely on the push rod. If it does not, you tend to rotate it and the push rod as you pump. That unscrews the nut off the bottom.

The pressure relief valve is another common source of pressure leaking. Unfortunately, the last time I checked, they are NLA, so do whatever you can.to align it with the old imprint.

[outboardboy3]

Ok great, what would be the best way to seal it, any type of sealant?

[frankr]

You only need a drop, so whatever you have on hand, as long as gas doesn’t dissolve it.

[Author]

Posts