Interchanging lower units

[duffer1960]

Could anyone tell me if the drive shaft of the lower unit from my 1968, ( 500, 50 HP) Mercury outboard. ( in-line 4 cylinder) would fit in the powerhead of a 1965, 65 hp, in line 4 cylinder model? I need to replace my powerhead, or find another that will fit the lower unit of my 50 hp mercury. A gentleman has a 1965, 65 hp with a blown lower unit and I can get the powerhead for a very reasonable price, but I do not know if the drive shaft of my lower unit will fit in the 65 hp powerhead. (number of splines?) Thanks for any helpful info.....

 

[Faztbullet]

Re: Interchanging lower units

Nope as the 50 is small diameter gearcase and shaft...

 

[carholme]

Re: Interchanging lower units

Duffer;

What happened to your 500 powerhead? I have the same, s/n 2347651, just converted to a long shaft. Great engine.

carholme

 

[duffer1960]

Re: Interchanging lower units

I bought it for a winter project. I assume the outboard was neglected. That seems to be the biggest reasson for problems with outboards up here in the north...... The bottom 2 cylinders have low compression,,, #3 cylinder,,,80 psi,,,,,, #4 cylinder is 0 psi.... I think that a previuos owner wasnt worried about oil/gas ratio....

 

[Faztbullet]

Re: Interchanging lower units

Sound more like bottom crank seals worn out/damaged and water was injested into bottom cylinders, very common on the older inline engines ...