Older omc fuel tank

[Travis.Bernard]

I have an older omc fuel tank and it has like five prongs on it does it take a certain hook or just the basic hook up? New to boating any help would be great

 

[southkogs]

Look like this?


Those are older outboard tanks. Whatcha' workin' on?

:welcome:

 

[Travis.Bernard]

My dad bought a 70s something boat with a mercury 65 up put board motor so trying to get everything hooked up to test did t have a fuel line with it

 

[southkogs]

Y'know ... now that I think of it ... I don't think I've ever seen a Mercury fuel tank. All my outboards have been Johnson/Evinrude or so old nobody knows who built 'em. No clue if they're compatible or not.

 

[Travis.Bernard]

It's a 1976 bee craft tri haul with a 65 hp mercury outboard motor

 

[Travis.Bernard]

I guess my biggest question is you can use any fuel talk for any engine just have to change connectors. And southkogs it leaks from the connector you pointed at? Is that a vent or does it hook up

 

[southkogs]

I guess my biggest question is you can use any fuel talk for any engine just have to change connectors.

I don't know how easy it is to change connectors, but in theory - unless the tank is pressurized, the tank itself should work. Changes are you can find one on eBay nearly as cheap as you can make one (at least I would think).

And southkogs it leaks from the connector you pointed at? Is that a vent or does it hook up

I just grabbed that image from another topic. That was where a member was having a leak. The OMCs connected to all of those points.

 

[JimS123]

OMC tank fittings attach to the bare fuel line with a hose clamp. Mercs attach to a brass threaded fitting molded into the end of the fuel line. Buy a Merc fuel line and cut the tank end off, replacing it with an OMC male end plug. Then you can use an OMC tank on a Merc motor. For the reverse, cut off the end of the Merc fuel line (brass fitting and all) and replace it with an OMC female fitting.

 

[Texasmark]

The old original tanks used 2 fuel lines molded together as a pair. One was for fuel and the other for air pressure. You used to pump up the tank because the early outboards didn't have a fuel pump. Back when the tank was part of the engine gravity was your pump. Before redesigning the larger engines with pumps they just used your thumb as the pump and pressurized the tank forcing the fuel up and into the carb. No reason you would have to use the air pressure line. It would just function as a vent for the tank. As 123 said, get you a couple of hose barb to hose barb to hose barb connectors and make your own.

 

[Travis.Bernard]

Are you talking like a three way barb fitting? And here is a picture of fuel hook up on the motor.

The old original tanks used 2 fuel lines molded together as a pair. One was for fuel and the other for air pressure. You used to pump up the tank because the early outboards didn't have a fuel pump. Back when the tank was part of the engine gravity was your pump. Before redesigning the larger engines with pumps they just used your thumb as the pump and pressurized the tank forcing the fuel up and into the carb. No reason you would have to use the air pressure line. It would just function as a vent for the tank. As 123 said, get you a couple of hose barb to hose barb to hose barb connectors and make your own.

 

[JimS123]

That's a standard single hose Mercury male fitting. My previous comments will work.

 

[Texasmark]

That's a standard single hose Mercury male fitting. My previous comments will work.

+1 Yessir it is Merc.....single hose fitting for engines with a fuel pump and is not the old style OMC but you have some options on how to do what you want to do.

 

[Ned L]

OMC stopped using pressurized tanks about 1960. The top picture is newer than that, and not pressurized.

 

[Travis.Bernard]

So is the one I got pressurized?

 

[Texasmark]

So is the one I got pressurized?

As I recall the pressurized ones had a manual pump shaft sticking out of it and a solid, black, plastic cap with no vent. If I am thinking properly on this the two small diameter pins just above the right hand tube with visible holes are your vent and when the connector is mated and locked (by the two pins on the left side) the locking will force the pins in and open the interior of the tank for air replacement.

Your leaking is probably the 0rings in the hose end of the connection....look down into it and see if you don't have a black 0ring in there.

 

[Ned L]

The one you have is not pressurized. A pressurized tank has a cap that requires something like ten turns to remove and replace, usually a black hard Bakelite or plastic as Texasmark said (the later ones are about a 1/4 turn on and off).
Also, they have a small air pump button (about 1/2" in diameter) near the handle on the tank. You have to depress this button a couple of dozen times after replacing the cap, to pump air into the tank and pressurize it.
Those tanks also typically had the hose (a siamese hose, shaped like an "8") permanently attached to the tank. A quick connect only at the outboard.

 

[Texasmark]

Those tanks also typically had the hose (a siamese hose, shaped like an "8") permanently attached to the tank. A quick connect only at the outboard.

Funny how you forget little things. I recall the changeover you mentioned. Growing up I didn't know the reason for the double hoses. When OMC started putting fuel pumps in their engines and changed tanks, I thought the single hose was a lesser quality product than the dual and rejected the change. Course I was just a kid back then and not very bright....no experiences.

 

[gm280]

If the OP wants to use the old style 6 gallon metal tank, he can just change out the connector on the OMC type hose setup for his engine and happy boating. The tank doesn't care what type engine it is feeding. And those old metal tanks are very nice and convient to use and carry as well. JMHO

 

[Ned L]

If the OP wants to use the old style 6 gallon metal tank, he can just change out the connector on the OMC type hose setup for his engine and happy boating. The tank doesn't care what type engine it is feeding. And those old metal tanks are very nice and convient to use and carry as well. JMHO

Kind of , sort of, but not quite true.
The old style tanks were pressurized, so there is no vent in the cap. The engine will run for 5 minutes or so until it draws a vacuum on the tank and the engine runs out of gas. I suppose if the air feed for the second (air supply) tube in the hose were left open it would vent the tank, but then you have no way to close off the 'vent'. ..... really just not a good way to do it.
And I really don't think this is what the OP is talking about anyway. The picture that Southkog posted in the second reply is of the first generation of the newer (after 1960) single hose design used by OMC.
The OP posted a picture of a Mercury (or maybe Chrysler?) hose connection on his engine. Yes you could easily make a cross conversion fuel hose to run the Mercury engine off the first generation non-pressurized ONC tank.
You do also have to be aware that after the single hose (non pressurized) tanks came out there were two different quick disconnect styles of hose connections used by OMC. The earlier one had the five "posts" as Southkogs pictured. One post for the fuel (small holes in the end of it in the photo), one post for the latch ( the post with the groove cut around the end of it in the photo), one post that was only a keying pin to keep you from connecting the hose backwards, and then the two small pins, which as I remember were spring loaded (when no hose is connected they are in the 'out' position and actually shut off the fuel to the fuel line so the tank doesn't leak gas as the day warms up and things expand, when the hose is connected they are pushed in, allowing gas to flow.) After a number of years of this style OMC simply made the fuel supply post and the latching post (or pin) different sizes so you couldn't connect it backwards.

 

[gm280]

Ned L, I do understand what you are saying. But when you plug on the OMC type fitting to the tank side, it pushes in on the vent plug and vents the tank at that time. So it stays sealed carrying the tank to fuel it up, but vents when connected up to the fuel fitting. I have two such tanks.