What grade gas to run in '78 Johnson 135hp

[Mikeyboy]

I recently bought a boat with a 1975 Johnson 135 horse power motor and I was just wondering what type of gas I should be running. Regular premium should I be running additives like octain boost. May be dumb questions but I'm a noobie. I appreciate and advice I can get. Thanks all.

 

[JB]

Re: What grade gas to run in '78 Johnson 135hp

Unleaded regular, Mikey. Mix it at 50:1 with TC-W3 outboard oil.

 

[Mikeyboy]

Re: What grade gas to run in '78 Johnson 135hp

Great thanks for that. Just wanted to make sure I wasn't doing something stupid.

 

[5150abf]

Re: What grade gas to run in '78 Johnson 135hp

2 stroke outboards are low compression engines and run fine on regular unleaded, there are some high power 4 strokes that take higher octane btu your old Johnson will be very happy wiht unleaded regular, if you want to put something in the gas Sea foam works really well to keep the engine clean and it stabilizes the fuel.

 

[Mikeyboy]

Re: What grade gas to run in '78 Johnson 135hp

Ok gotcha. I was mostly wondering because I know in old cars you typically need to run premium and octain booster. I am new to 2-strokes and didn't know if the same was true. Thanks for the advice.

 

[Bob_VT]

Re: What grade gas to run in '78 Johnson 135hp

Ok gotcha. I was mostly wondering because I know in old cars you typically need to run premium and octain booster. I am new to 2-strokes and didn't know if the same was true. Thanks for the advice.

There are no valve seats like the older cars and the TCW3 oil is the lubrication.

 

[Mikeyboy]

Re: What grade gas to run in '78 Johnson 135hp

Great thank guys for the advice.

 

[Silvertip]

Re: What grade gas to run in '78 Johnson 135hp

Higher octane fuel was needed in older cars because of the much higher compression ratios. High octane fuel does not make more power. It is simply required to prevent detonation in high compression engines.

 

[Skeeterbait]

Re: What grade gas to run in '78 Johnson 135hp

Also if you can find ethanol free fuel in your area, use it, no matter what you have to pay for it. That is true of any outboard but especially our older motors. Not only does the alcohol eat up rubber parts in the carbs and fuel lines but it is also a moisture magnet. In any device where fuel sets more than a week the alcohol will draw water out of the air. Our older motors are very sensitive to water in the fuel.

 

[Mikeyboy]

Re: What grade gas to run in '78 Johnson 135hp

I wish I could aviod ethanol but in my area we have been e-10 mandatory for a long time. We were one of the first areas to have it. Lucky us.