KBW10 Gear replacement or repair options?

[Freja2]

I have a KBW10 on my Yanmar 3JH2E on my new-to me boat, and it slips quite badly in forward (almost no thrust). I can't seem to find an aftermarket rebuild kit anywhere on the internet for these things. Hoping to either rebuild it myself (It'll be my first time tearing into a gearbox) or find a cheap replacement. By all accounts these should be a fairly common gear, as they were common on the 3GMs, but I am having a very hard time finding parts or any kind of a service manual for them.

Does anyone have any info about these transmissions and the availability of parts for them?

I've heard they were based off the very similar Hurth HBW 10, and I have found a rebuild kit that includes the clutch plates for that for only $250. Are these interchangeable at all? Even just being able to use the clutch plates is a huge gain, as the only other source I've found wants $189 (Canadian bucks) a plate, in a transmission that takes 8 plates.

Any help would be much appreciated!

[wsmurdoch]

Contact Rick Neary at East Coast Marine Transmission in South Amboy, NJ. He rebuilt my Kansaki KBW10 after it failed, after another shop had rebuilt it, after it first failed..... Rick's repair worked.

[Wotname]

The 2QM20 / 3QM30 service manual contains a detailed account (chapter 9) on the repair / overhaul aspects of the KBW10A gearbox. I believe your transmission is a KBW10E but I don't what the differences are, if any. I think there is a copy of this manual in the CF library.

I do have pdf copy but it is 50MB so a bit hard to send by email. I could probably work out how to transfer it by some file transfer web programme if necessary.

I haven't had a KBW10A apart but it might be possible to reverse the friction plates in a pinch which should give forward thrust but slip in reverse.

There are several other transmissions with might be suitable for your 3JH2E . I'm thinking YP10 or KH18 but I don't know for sure.

[Freja2]

Thank you very much for the manual info, I'll try and look that up. Mine is specifically a "KBW10 ER" according to the side plate (2.45 ratio). If all else fails, I am definitely going to try and just reverse the plates. I also considered trying to find another (possibly already slipping) KBW10 for cheap and pulling the reverse plates to make up a whole set. I however have no experience with these, so it's a whole new world for me!

If anyone has an old KBW10 for sale (I'm located BC, Canada) I would be very interested!

[Wotname]

This might be helpful, KBW10A assembly from the manual upthread.

[Freja2]

Fantastic, thank you! Also found the whole manual thanks to your comment, which is incredibly detailed. Now I just need to find a sacrificial KBW10 to steal the plates from....

[Freja2]

Just a little update to this thread, since so many people provided suggestions and help:



I'm an idiot (knew that already, luckily) and when testing if the transmission slipped, was turning the output coupling to the right for my right hand prop. If anyone finds this thread in the future, that's the opposite of the direction the force actually acts on that. The transmissions will slip in the direction opposite of what it's meant to turn, and that's part if the design.

So once I had the transmission out and on a bench, I removed the shifter side plate cover and checked the insides: a moderate amount of worn clutch plate material on the bottom but nothing excessive at all. Upon reinstalling the side plate cover, discovered that moving the position it's mounted in (It has oversized bolt holes that go over studs on the side of the transmission) was able to adjust the shifting point, so now it properly "clicks" into gear in both forward and reverse.

Also, over the course of a 24hr haulout, discovered that the cutless bearing was entirely ruined: It had apparently overheated at some point in the past and the rubber slotted sleeve had melted to the shaft and was providing a huge amount of resistance to turning the prop as it rotated inside the brass outer sleeve.

I have yet to reinstall the transmission, but I'm hoping it'll be working properly now that these multiple issues have been solved. Will be changing the ATF at frequent intervals for the first little while, I think, but hoping it'll work for a while. Currently waiting on an engine mount that was also discovered during the whole process (which may have also been part of the issue: alignment problems exacerbating the cutless bearing wear, which then failed and caused transmission problems.



Will update once I have it in and working again if anyone's interested!

[Bycrick]

We had about a dozen of these transmissions. They can be fixed, but our mechanic had some special tools that made the fix reliable. Until he got them, it was a crap-shoot whether a repair worked right. The parts were all available from Yanmar, with the cone being the most expensive. If you need an expert, PM me and I’ll give you his email address.

[Engine man]

I have a newly rebuilt Kanzaki KBW 10 transmission that includes a 2 year warranty. All OEM parts professionally installed. 2.14:1 ratio. $4350. Core charge $750. Shipping is additional.

Please contact me with any questions. Joe

Originally Posted by Freja2

I have a KBW10 on my Yanmar 3JH2E on my new-to me boat, and it slips quite badly in forward (almost no thrust). I can't seem to find an aftermarket rebuild kit anywhere on the internet for these things. Hoping to either rebuild it myself (It'll be my first time tearing into a gearbox) or find a cheap replacement. By all accounts these should be a fairly common gear, as they were common on the 3GMs, but I am having a very hard time finding parts or any kind of a service manual for them.

Does anyone have any info about these transmissions and the availability of parts for them?

I've heard they were based off the very similar Hurth HBW 10, and I have found a rebuild kit that includes the clutch plates for that for only $250. Are these interchangeable at all? Even just being able to use the clutch plates is a huge gain, as the only other source I've found wants $189 (Canadian bucks) a plate, in a transmission that takes 8 plates.

Any help would be much appreciated!