I know this will get interesting. For those of you not smarter than the engineers at Yanmar, this TSB may be beneficial for you.
We finally have a definitive statement from Yanmar on the proper gear position to use while sailing. According to the guy I spoke with this does not apply to hydraulic gear boxes or the few models that used Hurth/ZF.
Advisory Number: MSA08-003:
DATE February 8, 2008 Dealers and OEMs
TO: All Marine Distributors
SUBJECT: Gear in Neutral While Sailing All MODELS:
All Sailboat Engines
We continue to get questions regarding the correct gear position while sailing with the engine OFF. This advisory is issued as a reminder; Yanmar requires that if sailing with the engine OFF (not running) the transmission shifter must be in the neutral position or internal damage to the gear or sail-drive will result. This damage will not be covered by Yanmar’s Limited Warranty. Please instruct customers and dealers who deliver the sailboat to the customer, of the correct (Neutral) position for the marine gear while sailing.
If the customer desires that the propeller shaft not spin while sailing, either a folding propeller, shaft break, or other suitable device may be used. However, Yanmar accepts no responsibility for the selection, installation, or operation of such devices. Please also refer to Marine service advisory “MSA07-001_Yanmar Sail Drive Propeller Selection” for additional information.
If you have any questions regarding this advisory please contact a Customer Support representative.
Before folks ask, the reason for failure mode, as was describe to me, is that in reverse the clutch cones can chatter or vibrate against one another causing wear which eventually leads to slippage and a gear box re-build. Many already know how difficult a Kanzaki can be to get out of reverse after sailing with it locked.
Here's a quote from SBO:
Unfortunately I can attest to the proper Yanmar gear position. In the summer of 2008 my transmission (Kansaki on a 3GM30F engine) started slipping. Engine had 440 hours. always placed gear in reverse when sailing. After considerable discussion with Yamnar they advised they would not consider warranty (was passed the hours for that anyway). Upshot is new transmission. They advised that the cone clutch does "quiver" (my term) even though locked into reverse, producing wear and eventually slippage. [b]
Also, I am trying to cover all the bases because I know how this thread will go as I have posted this TSB on other forums.
1) Yes, it mentions sail drives but this is in reference to another TSB bulletin.
2) Yanmar chose their words very carefully. They did not use words like "suggests", "may" or "might" they use and chose words like "requires", "must" and "will" these words are never chosen lightly in the world of manufacturing. I think the key wording is as follows:
"Gear in Neutral While Sailing All MODELS: All Sailboat Engines"
"Yanmar requires that if sailing with the engine OFF (not running) the transmission shifter must be in the neutral position or internal damage to the gear or sail-drive will result."
P.S. Sailnet will not allow me to upload the .PDF file of the TSB if you want to see the actual document you can find it here.
Disclaimer: I do not have a dog in this fight as I do not currently own a Yanmar. I post this because it is a topic that comes up often and Yanmar never addressed this well in their manuals. I know many have sailed for years locked in reverse with no problems but they have apparently had enough failures to warrant the strong language and publishing of this TSB..