K case I.D. no casting numbers

[mikesea]

Hi Folk’s,
Just wondering what this case is from no casting numbers?

Thanks,
Mike

[20mercman]

It’s either a Mercury Mark 15 or 20. Most likely a Mk-20 as there were a lot more of them built. The boss on the starboard side is for mounting the linkage for the throttle/magneto. The boss on the port side is for the air pressure pump for the pressure tank.

Steve

[mikesea]

Hey Steve,
Thank you very much I am new to outboards and never saw this style of case.
Mike

[dave-bernard]

I would lean more toward the Mark 20 due to the size of the carb opening.

[foot_doctor]

It’s pretty simple to tell the differance between the MK15 and MK20 cases. The MK20 was equipped with the larger, high speed SJ7173 roller bearing. The Mk15 used the full complement Torrington drawn-cup needle. In addition they both had the same size carb opening, but you should be able to discern the outward appearance of the MK20 case by the flat almost rectangles cast on the exterior of the bottom crank throw areas

[mikesea]

Ron,
It had the 7173 bearing assembly in it.

Thanks,
Mike

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