mounting plate bolt pattern

[brokenwrist]

If I decide I ever want to repower my boat as it has a 79 70hp chrysler on it right now, could I reuse the two lower bolt holes that are currently drilled through my transom or would I have to plug and seal those and drill new bolt holes?

 

[Nordin]

When you says repower, does it mean you decide to put a Chrysler/Force engine at the transom or another brand?
If you decide to put Force or Chrysler the bolt pattern maybe will be the same then you can reuse your existing holes.

I am not sure if the hole pattern is the same for all 3,4 and 5 cylinder Chrysler/Force engines.
Have not worked with all Hps of them but I think they used the same transom clamps for most of them.

If you put another brand at the transom, then you have to drill new holes.
There are no standard pattern for OB.

 

[brokenwrist]

I found a complete ready to go 1990 60hp johnson with controls and oil injection tank. So I was wondering if all makes of outboards used the same mounting pattern or if they were all different

 

[roscoe]

No Title

There is a standard bolt pattern, but companies adopted it in different years.

johnson/Evinrude in the 70's, Merc in the early 80's, Force in the early 90's.

The BIA standard used on all modern motors is below.

 

[jerryjerry05]

Your Johnson won't match the Chrysler holes.
​Your controls won't work either.

They used the same bolt pattern until 88 then the screw down clamps were replaced with bolts.
Then in 92-3 they went to Mercury transom clamps and the bolt pattern went to the Mercury one.
Maybe?? your local boat dealer has a template for mounting??
Or make your own. Piece of plywood 12" X36" mount to the motor and drill holes.

If you have wood in the transom.
​What I did: use a bit that's just a little bigger and drill new holes.
​Get a hardwood dowel that is the same size as the new holes.
​Mix some fiberglass and coat the inside of the hole and coat the dowel.
​Drive the dowel in the holes.
​Make sure its flush.

​Let it dry 2-3 days and finish.
Sand it smooth and paint.

 

[Nordin]

Roscoe ....thanks for the information about the standard for the bolt pattern.
Did not know it, you learn something new every day.