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[weedlessdrive]

what gear cases fit a 58 johnson 10hp to interchange? Are there some that cross fit
Thanks

[Mumbles]

’58 to ’63 Johnnyrudes will all interchange. I have used a later 9.5 gearcase on a ’59 Johnson QD after swapping out the drive shaft and pinion gear. 😉

[weedlessdrive]

Is the 7 1/2 hp the same?thanks

[Mumbles]

The dimensions and gears are basically the same but the 7.5 has the shock absorber pinion shaft and the bushing ID is smaller than the ten horse drive shaft. Sorry, wont work.

[fleetwin]

Yeah, the 58-63 10hp gearcase is pretty unigue. The tough part to find these days is the driveshaft, the extra power was tough on the smaller gearcase when water got inside. Most 10hp driveshafts are worn in the lower bushing area, the lower bushings in the gearcase are usually whooped out as well. Complete 10hp gearcases will swap out from 58-63 but be careful trying to mix/match parts between different gearcases, the driveshaffts and gears changes around 1960.

[phil-b]

quote fleetwin:

Complete 10hp gearcases will swap out from 58-63 but be careful trying to mix/match parts between different gearcases, the driveshaffts and gears changes around 1960.

Yes, there was a mid-year change in 1960 (QD-21 vs QD-21S) that I think changed the drive shaft from keyed to splined, and lowered the tooth count on the gears so they are beefier.

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