Will an OMC outboard portable 6 gallon gas tank work on my '54 johnson Sea Horse 25hp?

Question

I currently have a Johnson "mile master" tank on it which rusted through.

Answer 1

Probably not,  Johnson and Evinrude engines from the '50's had 2 lines going from the tank to the engine.  The tanks were pressurized via one line which then forced the gas out of the tank and into the engine via the other line.  Best to take the tank to an Evinrude or Johnson dealer and see if they can help you get the proper tank, connectors and hoses that you need.

Answer 2

Yes, it should. You may need to change the fitting, but it will work.

Regards,

Dan

Answer 3

Your tank is most likely a two line unit, which takes crankcase pulses to pressurize the tank and "push" the fuel in to the carb.  You must have this type of tank since your engine was not built with a fuel pump.  Personally, I convert these engines and install a universal type fuel pump, available from Dennis Kirk or any other snowmobile parts catalog.  Mikuni pumps cost roughly $20, and you need drill, pipe tap, hose fitting, and some decent mechanical skills.  You have to tap into the bypass cover to get a vacuum pulse.  You need to know what you are doing, but there articles out there on the web.  Otherwise, look for a two line tank.  They are getting rare, and go from $50-$100 on Ebay, if in good shape.  If you convert the engine, you can use any old Walmart plastic tank and a Johnson or Merc connector.

Good luck.

Answer 4

Yes, if the gas line connections are the same, it should.

We swap tanks around all the time between our Johnson and Evinrude outboards. As long as the gas is mixed the same. We have several 50:1 engines and one 100:1 engine, don't cross those tanks.

The tank is just a reservoir for fuel, as long as the connections are the same, try it.