Kanzaki KM3-A unusual for a 2GM20F?

[bugbitten]

A sailing friend has a significantly faster (bigger) boat. I thought I might try to even things up a bit with a folding prop, but the prop company not surprisingly wanted to know what my transmission's ratio was. It took some paint stripper to get down to it, but it is 2.61. While uncovering that, I also discovered that it's a KM3-A, not the KM2-A one usually - or so I thought - associated with the 2 cylinder Yanmar. Is this an unusual pairing and, if so, any cause for concern? I noticed that this is the middle ratio of the three offered and is the only ratio that has a matching one on the KM2-A. The engine does seem to be able to reach its maximum RPM (or close to it) with a clean prop.

Of course, it did occur to me that this might make the upgrade to a 3GM a bit easier!

BTW the chainplate knee is done and the boat is ready (except for a ton of tools, etc., scattered in the cabin) to get out on the river once again.

John

 

[indimini]

First, congrats on getting the chainplate knee finished. I was able to get my deck rot cleaned up and reglassed, but won't get to replacing the rot until this weekend (weather permitting).

Looking at the Yanmar maintenance manual (http://j30.us/files/YanmarGM&HMWorkshopManual.pdf) the KM3 is definitely not the standard transmission for the 2GM20F. Is there any chance that there was a transmission replaced sometime in your boat's history?

 

[bugbitten]

When I bought the boat, the surveyor said that the engine was not original, so maybe something was cobbled together. I may have to dig around and see how narrowly I can pin down production dates by serial numbers. It all works fine, so no huge concern. Seems odd, though.

Now for an update on the HVAC install!

John