Is it possible? 650 to 850!

[Ironpig]

I am wondering what the differences are between a thunderbolt 850 and a thunderbolt 650 and if a 65 can be switched to an 85 horse engine with carbs and reeds, etc? Any thoughts from the board?

 

[79Merc80]

Re: Is it possible? 650 to 850!

From my understanding, the differences are the size and placement of the intake and exhaust ports on the block. I think the only one that was able to make that kind of change was the 1971 1150. That model was able to be pushed up to a 1350, but that was the only one.

Craig

 

[Droll]

Re: Is it possible? 650 to 850!

Well, the old ( late 60s ) Merc650 was a 4 cylinder crossflow engine, closest engine back then was a 80hp inline 6 engine ( crossflow ) .

The later Merc650 ( mid 70s ) was a 3 cylinder DC engine ( Direct Charge ), at that time there was a Merc850 but this was a inline 4 engine ( also DC engine ).

Only upgrade I can see are to switch the whole engine .


Arne Kjetil