A Definitive Answer (YANMAR Gear Position)

[kloudie1]

I guess I can see a case where the gearbox might be highly loaded in forward and heat things up a bunch and maybe heat the cup a little more than the cone? ( I dunno how Ed Zachery..?? The cone might lose some heat through the output shaft and the cup would see only the hot oil?) when when ya lock it in reverse, the thing would kinda shrink fit together and make it very difficult to get out of reverse. Wouldn't take much of a temp difference.. or maybe the little vibes from the stationary prop and the constant slight pressure of cone on cup might wiggle it together very tightly..?? I never thought of it much but I know on a couple of occasions over the years, mine had to be started in reverse to be able to get it into neutral, but that is normally not the case. So now I have a better argument for a feathering prop! Yea!

 

[Absolutely]

Catalina 36 Forward? Reverse? or Neutral?

Has Westerbenke weighed in on this yet?
In forward, much humming, friction, and you know that something is moving. In neutral, you can hear the spin and the whine. In reverse, I don't hear anything. Since I have the 35 hp and my boat (bought second hand) has a 2 blade prop, I will keep it in reverse until I hear something from the factory about this. I'll bet the guys with the three blade props really get the noise and friction. It seems very strange to me that this was never addressed before and with all the technology and upgrades by Catalina, if you need a prop brake, I would think they would install it a the factory and bump up the base price a dollar. Maybe the new models 350 etc, have something to define the answer to the problem.

 

[Don S/V ILLusion]

HI, this is my first reply to many many threads that I have read and enjoyed from this site. As a Marine Mechanic I am in awe that Yanmar came out and QUALIFIED what their recommendation is and what they require for waranty to be recognised on their tranmissions. TAKE NOTE that as Maine Sail said they have Qualified what their position is, and what, you still want to argue, I know from Experience that for Yanmar to ALLOW for it to be put in writing, Bloody do it, they might actually know what they are talking about as they MAKE them. If you have noise and vibration from your prop shaft turning, I know from experience, it is another problem, NOT the gearboxes freewheeling. If you believe that you need your prop shaft stationary, then fix a shaft brake and stop bitching. Happy Boating and smile you don't know how long you have, so enjoy.

It's a moot point in my case with a feathering Maxprop but any reasonably skeptical person who doesn't take everything as written would still question why they did this and also why they did not explain why they did this.
If I had a fixed prop, I'd tend to follow their recommendation but having said that, this still seems like a simple CYA statement dreamed up by their legal department to limit liability.

 

[John Gilbert]

On the Mooring

It's very helpful to know that the engine should be in neutral when sailing. I have an additional question. Our mooring is located in an area that sees quite a bit of current in the river, and I would like to know whether we should leave the engine in gear when it's sitting on the mooring or put it in neutral for the same rationale used by Yanmar in its guidance about sailing.

 

[Maine Sail]

Has Westerbenke weighed in on this yet?

Yes, see below..

In forward, much humming, friction, and you know that something is moving. In neutral, you can hear the spin and the whine. In reverse, I don't hear anything.

Most manufactures agree that forward is bad for gear boxes and Hurth/ZF specifically advises against forward.

Westerbeke / Universal has weighed in, and it is well known. ZF/Hurth or JS gear boxes used on Westerbeke & Universals can be left in both neutral or reverse but never forward when moving forward.

Some others, like hydraulic gear boxes, can not be left in neutral, no lube, so it is always best to consult your individual manual or manufacturer for your gear box.

Every gear box is different so it is always best to ask the manufacturer.

From Westerbeke / Universal:

UNIVERSAL DIESEL WITH HURTH TRANSMISSION

Model HBW-50 (2:1)
Used on Models 12, M2-12, M-18, M3-20, M4-30, M25 and M-25XP

Model HBW-100 (1.8:1)
Used on Models 30, 35, and 40

Model HBW-150 (1.9:1)
Used on Model 50

Model HBW-150 V-Drive (2.13:1)
Used on All of our V-Drive Models

Image Courtesy C-34 Association

 

[curley]

Up till now, I have always locked the shaft in reverse, (KM35P). I am guessing Yanmars alledged transmission damage from this could result from shift back to neutral with forward way on her prior to engine startup. With headway and the shaft locked in reverse position there is load on the tranmission. I always go below and physically unload the shaft then shift it to neutral locally. I would welcome to any ideas for a simple shaft locking device.

 

[scottthardin]

I bet I know why Yanmar has this position

I doubt much damage would be caused from freewheeling and I doubt much damage would occur when in locked safely in reverse. I can imagine damage coming from a sailor who is underway on a nice beam reach, beer in hand, doing 6.2 knots when he/she feels the prop vibration and decides that is the time to put the gear shifter in reverse.

 

[We2Sail12113]

Oh no, do I need worry ?

Finally, we have an answer. It fits well with the proven results that a freewheeling prop produces less drag than a locked one. But like Kloudie says any damage is probably insignificant as transmissions last 30-50 years.

Oh No, only 30 to 50 years ? Mine is aleady 32 years old. Do I need worry?

I can't see how a free wheeling prop spinning the tranny with no lubrication applied can be better than locked in reverse? Perhaps Yanmar is worried that if the prop shaft is in reverse, and IF the forward motion, under sail or tow forces the prop to spin backwards and damages the tranny, they don't want to be held liable ? ?

What's the likelihood of the engine restarting while off? Mine can start with a hand crank, but I can't see enough force to cause the reverse spinning shaft top restart the engine!!

 

[Ron McCoy]

Where can we obtain the TSB? I checked the Hunter website (bulletins, tech spt) and it wasn't listed. If it wasn't for this website, I wonder how Hunter expected to get the word out to owners of older Hunters, (maybe it's not important to them, since it beyond the warranty period and becomes a mute point?).

 

[wrbeglin]

Shaft seal wear

Apparently neutral is better for the gearbox, but what about all the unnecessary shaft seal wear. On my 323, at anything over about 3 knots the prop spins the shaft in reverse.

 

[Maine Sail]

Where can we obtain the TSB?

Here you go..

 

[glengrey]

Experienced the problem

Unfortunately I can attest to the proper Yanmar gear position.

In the summer of 2009 my transmission (Kansaki) started slipping. Engine had 440 hours. I had always placed the gear in reverse when sailing. After considerable discussion with Yamnar they advised they would not consider warranty!!!!!!!!!!!!!!!!!!!!!!!! I needed a new transmission at my cost.:cussing:

They advised that the cone clutch does "quiver" (my term) even though locked into reverse, producing wear and eventually slippage.

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.






The guy from Yanmar admitted that prior to 2008 they did not take much of a position either way in regards to reverse or neutral, hence the constant confusion on the forums when talking about Yanmar's.

This info does NOT apply to other engine makers!

 

[Ron10155]

If the Prop shaft is free wheeling?

We finally have a definitive answer from Yanmar!


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.






The guy from Yanmar admitted that prior to 2008 they did not take much of a position either way in regards to reverse or neutral, hence the constant confusion on the forums when talking about Yanmar's.

This info does NOT apply to other engine makers!

If your prop is free wheeling then there is the chance of excess wear on the cutlass bearing and stuffing box, personally I would rather fix a transmission, (they can't be that difficult) rather than hauling the boat, pulling the shaft replacing the cutlass bearing, installing the shaft, redoing the stuffing box, checking the shaft alignment, and putting the boat back into the water, before Yanmar starts making these claims and everyone accepts them at face value maybe we should find out what is being damaged by putting the prop in reverse.
Thanks Ron

 

[Max15631]

I wonder if we contacted the individual marine transmission manufacturers we could get a definitive answer from each of them. I don't believe that there are that many, and this would really put the issue to rest!

 

[Maine Sail]

If your prop is free wheeling then there is the chance of excess wear on the cutlass bearing and stuffing box, personally I would rather fix a transmission, (they can't be that difficult) rather than hauling the boat, pulling the shaft replacing the cutlass bearing, installing the shaft, redoing the stuffing box, checking the shaft alignment, and putting the boat back into the water,

Some thoughts..

1- If you pull the gear box to re-build you will need to do a re-alignment. You may also need to move the engine forward off it's mounts to get the gear box off the bell housing and have the clearance from the shaft. Been there done it..

2- You eventually need to haul to paint the bottom you can do a cutlass bearing at that point. They still can last thousands of hours if aligned properly. Many yards uses presses that do not require pulling the shaft. Runs about $200.00 +/- depending upon how greedy your yard is. The one in my boat lasted 3k engine hours and was still nearly usable for another season..

3- Re-packing a stuffing box is a 20-30 minute job and can be, and is often done, in-water. The packing costs about $6.00 - $12.00.

4- Gear boxes are not an easy re-build many of them require specialized tools, presses spanners etc. etc.. Gear box re-builds can run into the thousands of dollars as they are labor intensive and then will require an alignment and often re-positionaing of the engine back where it belongs...

before Yanmar starts making these claims and everyone accepts them at face value maybe we should find out what is being damaged by putting the prop in reverse.
Thanks Ron

See post #14 and # 32, the one directly above yours, that both describe the failure mode with a Yanmar / Kanzaki gear box reverse issue...

 

[secondwind410]

slipping?

I was wondering what you meant by slipping with your old transmission. I have one that has a periodic clunk. I am trying to troulble shoot the problem.

Unfortunately I can attest to the Yanmar 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.

 

[Elwin]

Neutral can be bad for your teeth

I bought a new Beneteau 43 last year, and indeed was told that neutral is the only way to go according to Yanmar. That is just fine if you're cruising along at under 5 knots but as the speed cranks in so does the vibration from a very large spinning 3 blade prop. Needless to say after weighing my options and not wanting to mess with the warranty issues, I have decided to go folding (Gori). Outside of the initial outlay, I'm not terribly upset as my last boat had a Maxprop and it's performance definitely improved after the installation.

 

[rodsailshunter5020]

I notice it says sail drive There is a difference and not to many of us have them in our Hunters.

 

[Maine Sail]

I notice it says sail drive There is a difference and not to many of us have them in our Hunters.

Post #14 (LINK) answers this.

The ONLY place sail drives are mentioned is in reference to ANOTHER TSB on propeller selection for sail drives.

"Please also refer to Marine service advisory “MSA07-001_Yanmar Sail Drive Propeller Selection”"

 

[freedom]

Bill Hunter 42

I mark the shaft with the prop vertical when a 2 blade and use visegrips for the shaft lock in neutral. No noise. No lip seal wear. Worked fine for 50,000 miles. Set grips light enough so when you forget to unlock them they slip as a rude reminder.