Re-jetting older Johnson for modern fuel

J

jimibee

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Jun 19, 2003
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OK I hope we have an OMC guru out there. I have a 1979 Johnson 235 HP outboard that I just rebuilt. It runs great, but before I put it under load I was curious if there are factory recommendations for enlarging the low and Hi speed jets for modern fuel,( up to 10% alcohol)? I have installed fiberglass reeds,( which require opening the stock Low speed (.032") jets .002" to .034 total. Is there a need to open them up more for modern gas? I DO NOT use the reformulated fuel here in SE WI.
 
JB

JB

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Re: Re-jetting older Johnson for modern fuel

I agree with S&R, Jimibee.<br /><br />Avoid alcohol enhanced fuel if at all possible and don't mess with your jets further.<br /><br />There are too many parts in a '79 engine package that turn to goo when exposed to alcohol.<br /><br />Whatever fuel you use, the jets only determine the fuel/air mix and 10% alcohol still requires about 14:1 ratio, same as 100% gasoline.<br /><br />Good luck. :)
 
J

jimibee

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Jun 19, 2003
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Re: Re-jetting older Johnson for modern fuel

Thanks. I just wanted to make sure it didn't lean out.
 
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