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VacationLand

gas to oil ratio for 50hp johnson 2 stoke

10 posts in this topic

the title kinda says it all...

does anyone know what the proper mixture is for a 1970ish Johnson 50hp, 2 stroke outboard?

I have been mixing 50:1 so I dont undermix but after 1/2 tank or so the engin starts to kick and has breif moments of no power. and its not REAL smokey, but smokey.

thanks

VaCa

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I'd assume 50:1 like mine is. 1988 25H Merc. Try using Amsoil - it helps with the smoke.

Brief moments of no power could be air in the gas line or maybe dirty carb. Mine does that once in a while too.

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50:1 sounds right for that year motor but I will second the recommendation of Amsoil. The other thing would be your plugs. Are they clean and gaped correctly. I have always liked NGK on any 2 stroke motor because they just seem to run better.

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ok, I was thinking that (possibly) exess oil was building up in the cylendar and causing a miss fire one or twice. being a 2 stoke you would feel that pretty easly. the plugs are kind of fouled up but not badly. I cleaned them with carb cleaner and the boat ran like a champ for about 20 min then started with the go, go, go, studder studder... It seems to do it LESS in full throttle.

But 50:1 you say?

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as far as the plug gap goes, these are the flat gapless plugs. I thought of that then unpluged the spark and saw it was that style. I have been meaning to pick up new plugs but I havent done it yet.

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I think that you will find out that it will run a lot smoother with NGK. You will have to find out what is the recommended plugs for that year motor by either talking to a dealer or look it up in the plug guide.

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It looks like your motor is a 1971-1975 and the model is a sizzler and the plug would be a B7HS with a gap of .30 and should be found at most auto parts store.

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I have a 70 H.P. johnson, I run amsoil70-1, get those b7hs nkg and you will think you have a different motor

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AMSOIL SABER OUTBOARD run it like the bottle says at 100:1, it souns crazy but your motor will never run better, my motor is also old and studdered like crazy, i went through everything, and it turned out to be too much oil build up on the plugs. I swiched to amsoil and bam! a whloe new motor. on the old oil mix a could never troll without the motor killing and coughing, now with the amsoil it just purrrrrrrs. make the switch you wont regret it.

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