Can I swap a 1984 50 hp powerhead with a 1977 55hp ?

[103Control]

Hello,
Just checking to see if I can interchange these blocks for a quick fix.

Will a 1984 Johnson 50hp power head be mounted on a 1977 55hp Evinrude easy enough all dress with the 1977 coils, power pack and carbs to turn it into a 55hp power head ?

I'm assumeing that the 40's, 50's, 55's & 60's are pretty much the same power head for years just bigger carbs and up dated electronics cranking out higher RPM's

I was supprised to get 150 psi compression out of both cylinders compared to the 1986 40hp Suzuki that was sporting
a mere 106-9 psi per cyl., does 150 sound normal for OMC 50's ?

Thanks Again, AL

 

[Scaaty]

Re: Can I swap a 1984 50 hp powerhead with a 1977 55hp ?

Yeah, every thing is the same (on some other planet at least). I think you will run into some serious issues, and a Dealer Service dept has all those answers

 

[Rancherlee]

Re: Can I swap a 1984 50 hp powerhead with a 1977 55hp ?

Take a close look at them, I think they are pretty much the same (same displacement). My 79' 55hp and my brother-in-laws 84' 60hp look Identical powerhead wise. you could also go to the Evinrude website and check out the partnumbers on the crankcase and see if they match up.

 

[103Control]

Re: Can I swap a 1984 50 hp powerhead with a 1977 55hp ?

Good Idea I'll compare part numbers at my local dealer on this planet. From what I've seen looking into this power head, OMC has really gotten plenty of milage out of one unit from 40 hp's to 60 hp's in outboards to firepumps. I just have to figure out if the entire short block has stayed virtually the same through out the years, they sure do look like it but maybe not ?

I'll try to cross reference and post back, I was just thinking if my hunch was correct and someone had done it before or some trained OMC tech knew certain years can match up ?

Thank you for the imput, Cheers!
AL