OMC Pressure Tanks

[Randy White, Sr]

Just went thru this with my OMC Cruis-A-Day Jr 4 gallon tank.  From everything I read, the diaphragms with the extra hole were for use with the aluminum push button, the rod of which attaches to metal washers on both sides of the diaphragm.  Older designs came wing the hole and with later designs, you add your own hole.
As to the filler cap, mine had the chain slot in its washer and the beaded chain.

[Buccaneer]

Randy White, Sr wrote:

Just went thru this with my OMC Cruis-A-Day Jr 4 gallon tank.  From everything I read, the diaphragms with the extra hole were for use with the aluminum push button, the rod of which attaches to metal washers on both sides of the diaphragm.  Older designs came wing the hole and with later designs, you add your own hole.
As to the filler cap, mine had the chain slot in its washer and the beaded chain.

Not talking about the hole for the primer shaft, but rather the
big “extra” hole in my photo that has the question mark.

Tore apart another tank today, and it had a normal diaphragm
without the extra big hole.

Prepare to be boarded!

[RICHARD A. WHITE]

Buccaneer wrote:

Randy White, Sr wrote:

Just went thru this with my OMC Cruis-A-Day Jr 4 gallon tank.  From everything I read, the diaphragms with the extra hole were for use with the aluminum push button, the rod of which attaches to metal washers on both sides of the diaphragm.  Older designs came wing the hole and with later designs, you add your own hole.
As to the filler cap, mine had the chain slot in its washer and the beaded chain.

Not talking about the hole for the primer shaft, but rather the
big “extra” hole in my photo that has the question mark.

Tore apart another tank today, and it had a normal diaphragm
without the extra big hole.

Tom,
Notice in Randy’s photo, he has the same gasket you are referencing, with that big extra hole….
I would surmise it was the original gasket, that was changed, but seemingly no record of the change.

Richard

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

[Buccaneer]

Richard, thanks for pointing that out about Randy’s gasket.
Maybe some old timer will know what’s the extra big hole
use to be for.

Prepare to be boarded!

[Buccaneer]

Regarding the diaphragm with the extra big hole, it may have been
for an “under-pressure” valve, as explained by the article I just
stumbled upon in my files.

1951-1952_johnson___evinrude_gas_tanks

Prepare to be boarded!

[RICHARD A. WHITE]

labrador-guy wrote:

Well Buc I spent the cold aspect morning looking at my old pressure tanks.  I have three four gallon tanks.  I think that is what you are referring to as junior tanks.   I have two with plastic buttons and one with an aluminum button, all have the chain attached to them.  My old memory banks told me somewhere amongst these tanks there are some without the chain.  I found them, they were from the early 50’s.  One came with my 14hp rude.  The other came with my 51 25hp rude.  The boys will correct me if I am wrong but the tank we now call the tall boy was first, probably around 49 or 50.  Then they made a red six gallon shorter with a small decal on it.  Does you tank have a place for the cotter pin to hold the chain for the cap?  Those chains are kind of a pain if you are pouring gas out at the end of the season.  It may have been swapped some time in the past.

No idea what is going on with the diaphragm.

dale

Try this… Make your tank connection with a fitting but have the line for the fuel open so you can put it where you want…apply low air pressure and it should pump itself out..

Hope that makes sense

Richard

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

[labrador-guy]

RICHARD A. WHITE wrote:

labrador-guy wrote:

Well Buc I spent the cold aspect morning looking at my old pressure tanks.  I have three four gallon tanks.  I think that is what you are referring to as junior tanks.   I have two with plastic buttons and one with an aluminum button, all have the chain attached to them.  My old memory banks told me somewhere amongst these tanks there are some without the chain.  I found them, they were from the early 50’s.  One came with my 14hp rude.  The other came with my 51 25hp rude.  The boys will correct me if I am wrong but the tank we now call the tall boy was first, probably around 49 or 50.  Then they made a red six gallon shorter with a small decal on it.  Does you tank have a place for the cotter pin to hold the chain for the cap?  Those chains are kind of a pain if you are pouring gas out at the end of the season.  It may have been swapped some time in the past.

No idea what is going on with the diaphragm.

dale

Try this… Make your tank connection with a fitting but have the line for the fuel open so you can put it where you want…apply low air pressure and it should pump itself out..

Hope that makes sense

Richard

Ya Richard!   I had to read your response three times and I finally figured out what you were getting at!   Yes I am gonna try that.  I am always pouring gas from tank to tank.  I like to have two tanks and one of them full when I hit the water.   I might be able to make a siphon doing that also.

dale

[labrador-guy]

Buccaneer wrote:

Regarding the diaphragm with the extra big hole, it may have been
for an “under-pressure” valve, as explained by the article I just
stumbled upon in my files.

1951-1952_johnson___evinrude_gas_tanks

Buc I read the article link you posted.  I just had an experience with that subject.  I recently purchased some garden tractor tires at an auction.  That was on one of those days when it was warm out.  The tires were in storage some where, they were new on new wheels but they were mostly flat.  I piled them in my pole barn and forgot about them.  I probably won’t do anything with them until summer.   I recently walked by them and the tread was sucked in like a vacuum was sucking them inside out.  Temperature was a balmy 10 degrees outside.   Wonder if the change in temperature will crush my tanks.  I keep the caps tight to keep the condensation out.  Might have to re think that!

interesting for sure!  dale

[Randy White, Sr]

Now, a pin-hole in my pressure tank.  The OMC 4 gallon Cruis-A-Day pressure tank I just rebuilt, painted and installed new decals on, seemed fine, clean and almost no rust inside now has a pin-hole leak. Didn’t show up until I put in a couple gallons of gas and pressurized it.  Have looked at a couple YouTube vids from tank sealer manufacturers.  Understand the process but hoping this group can share any advice on the process and recommend which sealer is best. TIA!

[Buccaneer]

I don’t know which sealer is best, but I like using Kreem.
They say to use their “prep” before using the sealer, but
I buy a concrete etch solution that is phosphoric acid.
It gets rid of rust and leaves a coating that the coating adheres
to well.

Prepare to be boarded!

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Randy White, Sr

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