Prop shaft turns while sailing?
- Thread starter McIntoshUSA
- Start date
This is not a true Kanzaki it is a Hurth/Kanzaki and is much closer to a Hurth HBW gear than a Kanzaki with a cone clutch. All Hurth gears use ATF. With Hurth gears you can either lock in reverse or leave to freewheel but never leave it in forward.. Look closely at the logo on that rating plate and the cursive writing says Kanzaki above the word Hurth..
However I understand there were some mods specified by Kanzaki that Hurth built into that gear and I would still follow Yanmar's guidance on gear position, it won't hurt it any. That gear is splash lubed so no issues letting it freewheel. Theoretically there should not be any issues locking it, just as you can do with a Hurth/ZF but I don't know what changes were made internally for the Yanmar/Kanzaki Hurth built gears...
In all my talks with Mack Boring and Yanmar the issues have mostly been with Kanzaki cone clutch gears not necessarily the Hurth built Kanzaki's....
When you put the transmission in reverse with a Max-Prop the blades will deploy to reverse position and attempt to rotate the shaft. This loads the transmission - not good for the listed cone and disk type Kanzaki transmisions. Stop the engine in forward. Check for proper feathering by selecting neutral and looking/listening for shaft rotation (there should be none).
See item #4:
http://pyiinc.com/images/pdf/max-prop/max-prop_easy.pdf
Here is a question that I don't think has been answered yet. I spent over an hour searching...
What exactly causes the problem (slippage - or clutch/thrust washer wear I assume) when the Yanmar transmission is left in reverse vs neutral?
With properly maintained/replaced oil, there should be no additional wear with the prop spinning in neutral (no load and only a few parts actually turning).
But with the tranny in reverse, is there enough torque that the clutches do slip. Or does something else cause the damage?
Just curious,
Chris
What exactly causes the problem (slippage - or clutch/thrust washer wear I assume) when the Yanmar transmission is left in reverse vs neutral?
With properly maintained/replaced oil, there should be no additional wear with the prop spinning in neutral (no load and only a few parts actually turning).
But with the tranny in reverse, is there enough torque that the clutches do slip. Or does something else cause the damage?
Just curious,
Chris
In gear (forward OR reverse) your transmission wet disks or cones are locked up to your crankshaft and the propeller-driven shaft is loading/slipping against them. Shift to neutral and the transmission disks/cones can spin with the prop shaft. Better yet, fold/feather your prop and stop shaft rotation.
One problem I had Catalina dealer tell me about and friends experienced first hand on their Hunter 38 was that when in reverse while sailing there was just enough pressure on the transmission that when you try to shift to neutral to start the engine it won't shift. And then people try to force it to neutral and by doing so damage the shifter linkage. The dealer actually said that if you sail in reverse, start the engine in reverse and after it starts move to neutral. It will shift easily this way. Or better yet, he said sail in neutral with a feathering prop.
This was right before I got my hands on the Yanmar bulletin. That settled it for me since the boat was brand new and I wasn't going to void my warranty. And once I put feathering Maxprop on so many other things improved that I never looked back. AND I DONT MEAN TO START THE WHICH FEATHERING PROP IS BEST DEBATE AGAIN AS THERE ARE THOUSANDS OF POSTS ON THAT ALREADY AS WELL ?. LOL.
Surprised that this topic still brings on heated debate. Not to add fuel to the fire but have you considered the wear on the cutless bearing from the shaft turning.
Maine Sail:
Thanks for your take on reverse vs. neutral for the old Kansaki/Hurth transmissions. I'll be leaving in neutral when sailing forward from now on.
Just a personal story about the different lubricant nameplate specs for different manufacture dates of the same KBW 10 model. I am pretty sure that my transmission was fed motor oil for most of its life. That is what my PO wrote down in his maintenance log book starting in the 1980's which I inherited when I bought the boat. I later noticed the discrepancy with the ATF specification on my nameplate. The local Yanmar dealer/repair shop told me when I asked that motor oil probably didn't do any harm (reasonable assumption since the gear box was still working fine after 28 years) but that I should change over to ATF. Which I did.
yanmar and borg warner -- neutral and let it spin ..it wont reduce sog at all. with my boat, i noticed there is no difference in sog when spinning vs fixed.
mechanics and info on my tranny have told me leave in neutral--aye aye, done and done.
mechanics and info on my tranny have told me leave in neutral--aye aye, done and done.
Gunni, I think it is the other way around, it is the rotation of the shaft creating a strong enough centrifugal force that will cause the blades to deploy according to their design in the direction of rotation. Once the blades feather there is not enough centrifugal force to be gained from the flow of water until you turn the engine back on and engage the transmission.
Zee, on a thirty ton boat such as yours, I would not think there would be one bit of difference dragging a static prop. Unless it's a biggun..
(I swear I don't mean that as sarcastic as it sounds, I'd love to have that Formosa..)
(I swear I don't mean that as sarcastic as it sounds, I'd love to have that Formosa..)
my crab crushing deep keeled magnifico is awesome. is just ugly enough to repel boarders and it is just gorgeous enough to look sweet from 100 ft.
perfect.
yes, it is most incredibly difficult to find some way to slow this beastie down, but my last alleged helper managed to do so . i think it is called " dont maintain my engne the way i requested, please."
as for your reaction/response--i add "tee hee hee"
Woodster: Yes, I believe you! And as I noted in my last post, I did in fact change to ATF (albeit a more modern incarnation of) five/six years ago on my first or second transmission lube change after I bought the boat and when I noted the discrepancy between the PO's engine log history and the info on nameplate.
I subsequently bought a Yanmar 2QM20 shop manual for detailed information about my engine. It also calls for ATF types for the "clutch case" as follows:
Shell = Dexron
Caltex = Texamatic Fluid
Mobil = ATF 220
Esso = ATF
B.P. = Autron DX
(Wonder how many of these brand names can still be found! Let alone the company name!)
But my original point was to comment on the conflicting information that floats around. I again include the nameplates from two KBW10's. Identical except the serial numbers. The serial# 1223 nameplate gives the owner the option of ATF-A or SAE 20/30HD -- which I believe falls into the category of motor oil. The nameplate for serial #5432 (from my boat) shows ATF-A only. I wonder if Kanzaki/Hurth changed something in the design between the dates that the 4000 or so units where manufactured, or it was later determined that only ATF was best. Did the owner of #1223 ever get the word?
Or maybe it was noted that if motor oil and ATF were intermixed (say for top-off or if the pump out evacuation wasn't complete) that having two lubes mixed in the same clutch case might not be compatible. And of the two choices, ATF-A was preferred. That thought occurred to me when I changed from motor oil to ATF. I pumped out the motor oil and refilled with ATF. Ran the engine in gear for just a few minutes. Pumped out again. Then refilled with ATF. I am beginning to note maybe some leakage at transmission seal near the coupling. I can't shake the feeling that the change of lubricants might have had something to do with it. (But also the engine is 35 years on at this point!)
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it not a problem for me i just though everyone could benefit for the information on that page ...it is a bit confusing to some but with it in Yanmars own publication it should help clear things up some ...i was not directing it to you personally just though it would be helpful to be able to see it in writing now it will bring the question do i have a KM or a KBW it seems there will never be and end to this because we are always getting new members or late comers....isn't nutrition a wonderful thing