1968 Johnson 55HP - Drilling Mounting Holes

[atengnr]

Im going to be installing my outboard, and recently filled in the old holes, due to shoddy work of the previous installer of the motor. Now, I have the 12 7/8, 9 7/8 and 9 in dimensions, but how far from the top of the transom should I drill the top holes??

Any info on how to best drill the holes would be appreciated.

Thanks.

 

[HybridMX6]

Re: 1968 Johnson 55HP - Drilling Mounting Holes

I'm not sure how far, or if your's is different, but I've always just got the motor in place on the transom and marked the holes with a sharpie, then either drilled it out with the motor in place or slid the engine over so I could drill straight holes (otherwise you get sideways ones, in my experience).

 

[Tim Frank]

Re: 1968 Johnson 55HP - Drilling Mounting Holes

Im going to be installing my outboard, and recently filled in the old holes, due to shoddy work of the previous installer of the motor. Now, I have the 12 7/8, 9 7/8 and 9 in dimensions, but how far from the top of the transom should I drill the top holes??

Any info on how to best drill the holes would be appreciated.

Thanks.

I had a 1969, and the brackets are the same part # as 1968; I don't remember the actual dimensions, but I drew c/l of transom and referenced from there for Starboard bracket. The top of bracket was flush with top of transom. Marked the two hole locations and used a drill jig to drill the two holes perpendicular to transom. Then measure for port bracket using starboard as reference. This cancels any inaccuracy in installing the starboard bracket.

What are the three dimensions that you have included? I would have thought you only needed two.

 

[atengnr]

Re: 1968 Johnson 55HP - Drilling Mounting Holes

I had a 1969, and the brackets are the same part # as 1968; I don't remember the actual dimensions, but I drew c/l of transom and referenced from there for Starboard bracket. The top of bracket was flush with top of transom. Marked the two hole locations and used a drill jig to drill the two holes perpendicular to transom. Then measure for port bracket using starboard as reference. This cancels any inaccuracy in installing the starboard bracket.

What are the three dimensions that you have included? I would have thought you only needed two.

I picked these up from the forum in the past. 12 7/8 between the tope holes, 9 7/8 between the bottom, and 9 inches from top to bottom....Does this apply for the 68 motor??

 

[Tim Frank]

Re: 1968 Johnson 55HP - Drilling Mounting Holes

I picked these up from the forum in the past. 12 7/8 between the tope holes, 9 7/8 between the bottom, and 9 inches from top to bottom....Does this apply for the 68 motor??

Ok, that makes sense. The top to bottom measurement was not one that I used or needed by my method of installation. I drew the 12-7/8" and 9-7/8" reference lines, 6-7/16" and 4-15/16" respectively on each side of the centreline. Then drilled top hole on starboard bracket,and installed that bolt....then lined up bracket bottom hole on drawn line and marked and drilled that. Double check that everything lined up with the lines and make any very minor adjustments (if necessary) as you do the port bracket.
You do have to be careful that you do not get the top hole too low or the bracket locking pins will never line up with the holes in the motor.
If are very good at layout and drilling you can just measure, mark, and drill all 4 holes. Otherwise, doing it in steps is safer.

My comment about 1969 motor brackets was simply that the part #s were the same as the '68.
I don't know with 100% certainty that the installation measurements are identical, but I would be very surprised if OMC had any reason to change this.