Diff between Johnson 20 and 25?

Bearcamp

Petty Officer 1st Class
Joined
May 21, 2003
Messages
341
I have 2 1970 Johnsons. 1 is a 20 hp and the other is a 25 hp. What's the difference between the 2 as for as the 25 having 5 more horse. Is it just the carb?
 

dolluper

Captain
Joined
Jul 19, 2004
Messages
3,900
Re: Diff between Johnson 20 and 25?

reed openings and pistons different
 

Chinewalker

Fleet Admiral
Joined
Aug 19, 2001
Messages
8,902
Re: Diff between Johnson 20 and 25?

Hi Dolluper,<br /> I was aware of the reed stops being opened up more on the 25, but how are the pistons different? I've had several of both models apart and didn't notice anything obvious between them....<br />- Scott
 

G DANE

Commander
Joined
Nov 24, 2001
Messages
2,476
Re: Diff between Johnson 20 and 25?

I'v been told that the pistons were higher on the 25 adding compression, too the reason the 25 had extra weights riveted on the casted cranckshaft weights.
 

dolluper

Captain
Joined
Jul 19, 2004
Messages
3,900
Re: Diff between Johnson 20 and 25?

I stand corrected I should have said con rod
 
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