Late 70's early 80's 25-35hp...carb difference or?

[Shawnfish80]

Do the 35's get the extra 10hp from the carb having a bigger throat? Seems i saw the powerheads and manifolds are the same on both the 25's and 35's of this era, that being said it has to be the carb right??

 

[ct1762@gmail.com]

that and the INTAKE MANIFOLD. Big difference in size, plus i'm sure a timing advance vs the 25

 

[Shawnfish80]

that and the INTAKE MANIFOLD. Big difference in size, plus i'm sure a timing advance vs the 25

Hmmmmm.....i checked and all the 25's and 35's from 76 to 84 have the same intakes...according to the part numbers.
I guess im confused as to why the intakes would be different (size wise) but still have the same part #. ??

 

[matt167]

The original part numbers appear to be different. The latest part number appears to be the same replacement part for both. I did just a quick check for 1979 25 and 35. The 1980's motors I know are different. I looked into converting my 1988 20hp into a 30hp ( 35hp was de rated in the 80's )

 

[Dano3578]

80's johnson/evinrude 25hp to 30-35hp conversion with pics

Ok I know this thread has been rehashed several times but I decided to put pics of the modification up and point out the differences between the 25hp and 35hp. Although the 35 became the 30 after the prop HP rating in 85'. First is the carburetor difference: The 25hp is a 1988 and the 35hp is...

forums.iboats.com

You may find some answers here. I did the conversion on my 86 20hp last year. Man does she have some spunk!!