Questions on a Johnson Pressure Tank rebuild

[todd281]

I am in the process of rebuilding a Mile Master 4 gallon, two line, Pressure tank.[My first pressure tank project] I have it apart and have some questions about replacement parts. This tank has a primer pump, and the shaft of it, goes through the diaphragm [as show by the red arrow in the first picture] So far all of the rebuild kits I have found do not have a hole for it to pass through. [see picture 2] they also come with some replacement parts that do not look anything like mine. [pic 3] the part # I have is 377327. Perhaps that is incorrect, does anyone know the correct part #? Or maybe there is something that was changed to avoid the extra hole in the diaphragm . Any advise would be greatly appreciated

• This topic was modified 5 years, 6 months ago by Mumbles.

[frankr]

There are two types of pressure tanks (three actually). Those with a metal push rod & button, and those with a plastic push button. You simply have the latest type kit for updating early plastic button. No sweat, just punch a hole in the diaphragm and discard the plastic button.

[Tinman]

Two styles. One with a black primer button and one with an aluminum button. Different diaphrams. And a few different parts. Both kits are available. eBay sometimes has them. Vintage outboard may still have one available. Laings may have them too.

[todd281]

sounds easy I am off to e-bay..

[RICHARD A. WHITE]

You can also order the correct one from MarineEngine. there is a catch, they charge more for the diaphragm with the hole than they do for the one without. So I buy them without and punch the extra hole.

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

[todd281]

Well , that makes sense,, they have to pay someone to punch the hole before the send it out. I have one on the way , now to find a tank end fitting that I can afford.

[frankr]

Two types / three types. Not an issue here, but to explain, there were two types of plastic buttons. Early ones had two metal support disks riveted to the diaphragm. Those diaphragms are obsolete and are replaced by the latest type with no hole. The kit shown above updates the riveted one to the no-hole one..

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