1958 super sea horse 35 hp broken piston

[Woodstock60]

Thats what I have. I want to replace it with one from a 68 evinrude 33 hp powerhead- looks the same but I can't find any info to confirm.... any takers?

 

[F_R]

Re: 1958 super sea horse 35 hp broken piston

1958 piston is 377409
1968 piston is 380566

That means there is a difference somewhere, but offhand I don't know what it is. Guessing height (compression ratio) They both use 378436 ring sets.

 

[Woodstock60]

Re: 1958 super sea horse 35 hp broken piston

Thanks FR, I guess because they both use the same ring set I will break out my caliper and see if I can find the difference, I find that every once in a while a different part # doesn't mean you cant interchange- that being said I doubt that rule applies to pistons. Ronnie

 

[Woodstock60]

Re: 1958 super sea horse 35 hp broken piston

F R I have another question, This motor is a RDS 20, I also have a RD 19. Are these powerheads basically the same as far as crankshaft and pistons, and where can I find this information about early motor parts. Thanks Ronnie

 

[F_R]

Re: 1958 super sea horse 35 hp broken piston

Pistons and rings are the same, crankshafts are different.
Source, Johnson Quick Reference Guide, 1978 issue.