Outboard BIA Transom plate/jig

kingblazer84

Crew Member
Hey guys since im in the process of doing some research on swapping to 4 strokes from an old 75 merc 85hp, I thought id post what I found as far as a hole template for the holes needed to go from older power to newer power on your transom its a cut file that can be used by any shop with a plasma table or water jet etc.

here's a quick photo as well of the dimensions I'm referring to.
 

Attachments

Looks like you are going to do all the work yourself. Just a couple of things to look out for. Now I don't know what kind of boat you haveb but it would be a good idea to check the amount of "backslope" the transom has, that is the amount of tuck under in degrees it has. Some of the newer motors have less of a negative tilt then the older ones. You need about 12 -14 degrees of total negative tilt to ensure that the boat does not porpoise. Make sure that the transom is parrallel to the flat ground when marking where the bolt holes go, When drilling the holes, remember to drill at the correct upward angle. Have fun
 
I think Merc makes a fixture just for that. Didn't stop the moron that built my boat from putting the holes in a curved area of the transom so the top bolts actually have a gap between motor bracket and the transom.
Had to have transom reglassed so it was FLAT where the motor bracket is like it's supposed to be.

Screenshot_20210118-215227_Samsung Internet.jpg
 
Back
Top