OUTBOARD TRANSOM MOUNT HOLE LOCATIONS

kingblazer84

kingblazer84

Crew Member
So boys dont know if anyone can answer this or not as there is alot of convoluted info online about this topic. Im trying to repower my boat in the spring time and going from a 78 merc 850 outboard to a 98 honda 90hp outboard, does anyone know if there is a standard set of mounting holes on outboards that match up to all year models and makes? or is it brand specific and redrilling / filling the holes in the transom are needed?
 
Let me know if you would like any measurements off of mine, like width or spacing etc. Just shoot me a pm
 
Some of those older mercs had a different mounting template. Pretty sure if I can remember right they had large clamp screws on the top and 2 bolts on the bottom..?


Not sure where your located but I might lend you my drill template if you promise to bring it back. I'm in delta.
 
ship happens said:
Some of those older mercs had a different mounting template. Pretty sure if I can remember right they had large clamp screws on the top and 2 bolts on the bottom..?


Not sure where your located but I might lend you my drill template if you promise to bring it back. I'm in delta.
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In Kelowna, but maybe we can figure something out? my 850 thunderbolt bolts through the transom with 4 bolts not the old old t style hand crank ones, if I could borrow that template that would be sweet is it a jig or ?
 
kingblazer84 said:
In Kelowna, but maybe we can figure something out? my 850 thunderbolt bolts through the transom with 4 bolts not the old old t style hand crank ones, if I could borrow that template that would be sweet is it a jig
Click to expand...


Yeah it a jig. It has steel guides and uses standard 1/2 inch bolt holes. The guides allow you to drill holes exact placement and exactly square also. You dont want a hole to go through at an angle.

I can measure my jig for you tonorrow.
 
Not sure however this might help you?

Not sure why pics are upside down fyi
 

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how do your measurements match up to the ones on the Honda, KB?!
The measurements shown above by Ship happens (great name by the way) seem to match up to it.
 
Yeah I dunno, that's a tough task. Better off using the jig for sure. They hit on 16ths & 32nds so it's tough to make your own.
 
Last edited:
Stizzla said:
how do your measurements match up to the ones on the Honda, KB?!
The measurements shown above by Ship happens (great name by the way) seem to match up to it.
Click to expand...
Making some measurements tomorrow I have the dimensions I need Found some online as well
 
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