Old Johson 4 HP

[whitenoize]

I was given a johnson 4 HP that "runs great" but nobody can remember the gas/oil mix ratio or the particlarities of starting this one.It is a model 4w71D which if i understand another post i read means its a 71.For the life of me i swear there was MOTOR OIL in the fuel line is this right??I had read that a wc-3? rated oil was called for.

 

[REELSPORT]

Re: Old Johson 4 HP

the wc-3 oil is right and if it is a 1971 the mix rate should be 50-1

 

[REELSPORT]

Re: Old Johson 4 HP

As for the motor oil being in the gas line no that is not right motor oil does not mix with gasoline good enough to use with any 2 stroke

 

[Paul Moir]

Re: Old Johson 4 HP

Mix ratio is officially 50:1 as others pointed out. I run my '72 4hp at 32:1 for good reasons though - it's got plain bearings on the rod ends and all the main crank bearings but the top. It really appreciates the extra volume oil, and it seems those run with the recomended ratio don't seem to live as long. But 50:1 is what OMC said.<br />Forget about motor oil. It wasn't ment to be burnt. Like these guys say, use TC-W3.<br /><br />Starts like any other. Pull choke knob out, set throttle to 'START', pump primer bulb 'til hard, and pull the cord. If it chugs and quits, push in the choke and pull a couple more times 'til it goes.

 

[whitenoize]

Re: Old Johson 4 HP

Thanks so much for the confirmations and information fellas

 

[whitenoize]

Re: Old Johson 4 HP

Good news! Following your advice i pre-mixed at 32:1 with the proper oil and after clearing 3 fouled plugs ( yes somebody had put motor oil in the tank......)i fired it right up Which leads me to my next question: Does anybody know the correct spark plug gap for this motor?? It must be close now or it wouldnt run.

 

[Paul Moir]

Re: Old Johson 4 HP

It's .030". Champion J6C replacing the J6J plug.<br /><br />(Deja-vu. I just wrote the same answer in another post!)