What does this gearcase fit?

[Special K]

This gearcase is up for sale but the seller seems unclear as to what it fits. Ad says mk30H???. I’m sure you guys will know.

[DeanFHobart]

If the gold paint is original then it would be for a ‘Converted 20H Mercury’. The case itself could be used also for a Mark 30H Mercury with different bearings on the top of the driveshaft and a different driveshaft. The Foot Doctor Ron Thomas would know the exact different parts along with other people here. All of the other parts to make this a usable unit are available brand new. The cases themselves are the only parts not being made new. Even the paint is available.

This one looks to be in great shape... If I were you I would grab it for the right price, of course. I do not know the value.

[Special K]

Yes he does state it could also be a 20H and that the paint looks original and threads look as if it’s new old stock. Any chance this could be used with a different mid section to run 1:1 on s mk55?

[Special K]

I’ve seen pictures of homemade mid sections that have a plate made to fit the powerhead of the mk55 with a drive shaft tube to a gearcase plate to fit your gearcase of choice.

[DeanFHobart]

Yes he does state it could also be a 20H and that the paint looks original and threads look as if it’s new old stock. Any chance this could be used with a different mid section to run 1:1 on s mk55?

I don’t think so... the Mark 55 ‘D’ gearcases were larger... everything was larger. The gears bearings etc. would not hold up under a Mark 55.