28 to 40+?

6228SH

Petty Officer 3rd Class
Joined
Jun 14, 2007
Messages
77
I have a '62 28 horse Johnson-as written in other threads,I've recently got it ressurected and may or may not be at it's potential for powering my boat-if this is all it's got,I'd like to go with more power.In the back of my mind is a winter project of putting a bigger powerhead on or replacing the crank and rods,etc to stroke it into 40 horse(or more?)-it seems like OMC cranked out a zillion twin cyl engines that may offer me a bolt up bigger engine if I found the right parts...anyone know what my options are here?
 

tashasdaddy

Honorary Moderator Emeritus
Joined
Nov 11, 2005
Messages
51,019
Re: 28 to 40+?

sell what you have and buy a bigger engine, much cheaper in the long run. trying to find parts to fit is not worth it. if it would even work. these type things usually turn out bad.
 

WillyBWright

Fleet Admiral
Joined
Dec 29, 2003
Messages
8,200
Re: 28 to 40+?

Old Evinrude Larks and Johnson 40s are easy to find. Buy a few, make one. Leave the 28 a 28. They're different enough from a 40 to make it impractical to impossible. Maybe up to 35.
 

Chinewalker

Fleet Admiral
Joined
Aug 19, 2001
Messages
8,902
Re: 28 to 40+?

There is no way to "stroke" a Johnrude Big Twin. The same crankshaft throws/stroke length were used throughout the run. They simply bored the block out larger and larger to go from the original 1951 36-cubes too the final 44-cubes. As was noted, simply find a 40 and be done with it. Drop your 28 cowling on the 40 if you want to make it a "sleeper". Much easier than trying to mix and match parts...
- Scott
 

6228SH

Petty Officer 3rd Class
Joined
Jun 14, 2007
Messages
77
Re: 28 to 40+?

Thanks for the advice-I'll keep my eye out for something bigger if this 28 dosent work out-I'm hoping some experimenting with trim and prop change will get me up to speed though-this is a cool old motor! another ? on the same topic-my boat has nothing but a serial # on the transom plate-how do I determine how much is too much motor,should I come across one of the bigger models? the boat is a '60 blue star 16' alumn runabout.
 
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