Re: Converting OMC 5.5/7.5hp gearcase to ’58 10hp Gearcase

[chris-p]

Yeah for anyone doing this, just find a good original gearcase! I like to do things the hard way. Plus I usually have the parts to make it work.

So for those searching this in the future what I believe to be true is:

If you have a gearcase from a AD10M, or a CD-13A through CD-22M, you can make it work on the QD-19 through QD-24M by:

1. Changing out the shift rod to a 305319 rod
2. Changing out the drive shaft to a 305368 shaft
3. Changing out water pump housing (pn 310000 or 305302) complete with spacer and o rings on top (305552 for spacer)
4. If you have a QD-19 through QD-21, you can use the gear sets from the CD-12 through CD-22 (pinion gear changed on the CD- 22), or the AD-10 through AD-12
5. The SS impeller wear plate can stay, but the drive shaft housing and seal assembly will need to be swapped to the 377186 assembly with drive shaft seal 303345. The gasket for the seal assemblies is the same.
6. Changing the prop to a 377635 which is the original 8 1/4 x 8 1/2 3 blade. Drive pin obviously the same as same prop shaft.

So moral of the story, just buy a complete case.

Stay tuned for tomorrow overly difficult restoration 😉