Which OMC tank for my Johnson motor?

camhart · May 24, 2024

Hi, I just picked up a 1976 Johnson 35hp outboard model #35R79A, and I need to purchase a used metal gas tank and hose kit. This is my first Johnson/Evinrude, and I'm reading about pressurized and non-pressurized tanks. I've attached a pic of the fuel line connector, is this the "double-line" system I've heard about? There are many OMC metal tanks for sale on FB Marketplace, how do I know which tank will work with my boat? Thanks for helping a noobie out!

FuzzyGrub · May 24, 2024

camhart said:
Hi, I just picked up a 1976 Johnson 35hp outboard model #35R79A, and I need to purchase a used metal gas tank and hose kit. This is my first Johnson/Evinrude, and I'm reading about pressurized and non-pressurized tanks. I've attached a pic of the fuel line connector, is this the "double-line" system I've heard about? There are many OMC metal tanks for sale on FB Marketplace, how do I know which tank will work with my boat? Thanks for helping a noobie out!

That looks like a single line system. One “prong” is for the fuel, the other to hold the fitting on the motor. I believe most if not all of OMCs dual line pressurized tanks were phased out in the 60’s.

MDCrappie · May 24, 2024

The old dual line tank fittings actually have 3 "pins". One for each line and then a securing pin in the middle.

Pappy · May 24, 2024

There are both 3-gallon and 6 gallon single line tanks available for your engine. Both are metal and I would recommend you stay with a metal tank. Either purchase the OMC primer bulb and OMC fittings separately and add your own line or you can purchase the entire assy.
Stay away from cheap fuel system components!
Single line tanks will or should have either the older round sight glass in them or the newer rectangular one. Either one is fine however the newer design is a bit more friendly to repair if necessary.
A tell-tale sign of the need to repair on these tanks will be a fuel leak at the tank end of the fitting. If you see this then repair parts are available for the fitting including the tiny quad ring that is the usual culprit. Also keep in mind that a fuel leak in this location is also an air leak while at high RPM and load on the engine. Repairs are pretty easy and will probably last you throughout your boating career.

LaqueRatt · May 25, 2024

That's a standard OMC fitting. The pressurized systems were for older motors. Pre 70s I think. As for a tank, I'd go with whatever you can scarf up cheap locally. Metal tanks have their advantages, but so do plastic tanks. What you really don't want is a brand new plastic tank because they are unvented! EG: They blow up like a balloon in the sun.

Bianceferri · Sep 30, 2024

For your 1976 Johnson 35hp outboard model #35R79A, you'll need a compatible OMC metal gas tank that matches the "double-line" fuel system your motor uses. The double-line system requires a specific tank type, typically a pressurized one, that has two fittings: one for fuel supply and another for venting. When shopping on platforms like FB Marketplace, look for OMC tanks that are specifically designed for Johnson/Evinrude engines, ideally from the same era or with a confirmed compatibility with double-line setups.

A commonly compatible tank is the OMC 6-gallon or 12-gallon metal tank, which should have a proper fuel line connector that matches your outboard. Additionally, ensure the tank comes with the correct hose kit for a seamless connection. If possible, ask the seller for details or pictures to confirm that it’s a double-line tank before purchasing.

airshot · Sep 30, 2024

In 1964 OMC stopped using pressure fuel tanks and switched over to non pressure single line tanks. Check the inside of any metal tank and be sure there is NO rust inside !

mbullen · Oct 4, 2024

Bianceferri said:
For your 1976 Johnson 35hp outboard model #35R79A, you'll need a compatible OMC metal gas tank that matches the "double-line" fuel system your motor uses. The double-line system requires a specific tank type, typically a pressurized one, that has two fittings: one for fuel supply and another for venting. When shopping on platforms like FB Marketplace, look for OMC tanks that are specifically designed for Johnson/Evinrude engines, ideally from the same era or with a confirmed compatibility with double-line setups.

A commonly compatible tank is the OMC 6-gallon or 12-gallon metal tank, which should have a proper fuel line connector that matches your outboard. Additionally, ensure the tank comes with the correct hose kit for a seamless connection. If possible, ask the seller for details or pictures to confirm that it’s a double-line tank before purchasing.

Any 1976 OMC product has a fuel pump. It uses a single line tank with standard OMC fittings.
It does not use a dual-line, pressurized tank. (which, btw, the second line is not for venting, but for pressurizing)

Pappy · Oct 9, 2024

Any single line OMC fuel line fitting will work. There is no difference. They are all the same. Always buy quality!!!
The single line metal tanks are vented even though the cap may not be. The vent plunger is at the mating surface between the tank fitting and fuel line fitting on the tank side.

Which OMC tank for my Johnson motor?

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