Evinrude engine specs

[RicS1953]

I noticed in my '86 owner's manual that the Evinrude 20, 25, 30, and 35 hp all displace 31.8 cubic inches.
Does anyone know what (besides horsepower and propellers) the exact differences are between these
outboards? Can the 20, 25, and 30 be modified to 35, and if so, what all is involved?

 

[coueytwo]

go to this page http://www.marineengine.com/parts/parts.php
select each engine and see if they are the same.

 

[GotBoat]

Carbs, exhaust, head ports

 

[RicS1953]

I suppose the interest here is because upgrading my 25 to a 35 would mean a 40% increase in power- that's a pretty substantial increase, if it doesn't become too costly. My boat is rated for a 40 hp.

 

[GotBoat]

Then your best bet is to sell the motor and buy a bigger one. It would be the easy way.