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upgrade johnson 115?

P

plusoneten

New member
anyone know if its possible to upgrade a 1978 johnson 115 into a 140? I hear that they share a lot of parts.

or, if a full upgrade is impractical, can i swap carbs or something and pick up a few hp?


thanks
 
also, i run 90 octane gas in it... the local station has ethanol free 90 octane. i assume it was designed for 87 or maybe even lower...

think i might be able to advance the timing a bit? or wont that gain me much?
 
You're not going to turn a 115 into a 140 cheaply. I wouldn't mess with the timing either, there's really not much to be gained by that and a lot to loose.

IMHO, if you want a 140 then buy a good used one and sell your 115. I'd be willing to bet your checking account would end up miles ahead of where it would be if you purchased all the parts and paid for the machine work it would take to do the conversion.
 
port timming is diffrent, most 140s have bubble back exhaust, bigger carbs, and tighter heads, I have some 1 5/16 carbs for $75 if ya want em
 
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