1986 70 HP Mercury Outboard

[Kissdude]

I was wondering if someone could help me please! I have an older 70HP Mercury outboard serial number OA743766, I purchased this without the block, disassembled but has all parts. I have found a 75hp block and wondering if I can use it in place of the original 70 hp block. Thanks!

 

[Chris1956]

The 70HP motor would have 3 cylinders, I would think. The 75HP powerhead may have 4 cylinders, depending on the year. I expect the years to be quite different, I will guess early 70s for the 75HP powerhead. You will need to count and measure the powerhead mounting studs and see if they are the same number and length. If that matches, you can take the exhaust extension and see if the 75HP powerhead will bolt up.

 

[racerone]

Is OA743766 a Canadian serial # ??

 

[Kissdude]

Is OA743766 a Canadian serial # ??

Yes I believe it is a Canadian number