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Loss of drive on my Santorin


Grant Starling
 

I have lost drive on my Santorin.  It started when I replaced the morse throttle/gear selector and at first I thought it was bad cable adjustment meaning my gearbox clutch not engaging properly.  

Basically the problem is as follows.  I start the engine, select gear, when I apply power to accelerate, there is no increase in thrust from the propellor beyond that which I get idling in gear.  So I can move the boat around at idling speed in forward revers, but no thrust or increase in motion even at full revs.

So after adjusting the cable to ensure proper adjustment and still getting no joy, I looked secondly to the gearbox clutch as being the issue.  I thought at 30 years old its probably slipping and needed replacement.  So I rebuilt the gearbox with brand new clutch, bearings and seals.

Reinstalled it this morning.  Same problem is still there.....no drive.

The c-drive seems to be spinning up fine when I increase throttle, it increases in speed.  I can turn the c-drive by hand and it seem smooth and turns easy.  Put my GoPro on a pole and checked the propellor under-water, just to check there was no debris on it....it seems to be spinning fine.

So short of the propellor slipping on the prop-shaft, I am out of ideas?  

Has anyone had a similar issue?  What are the chances of the prop shearing it’s key and spinning on the shaft?  Sincerely hope this isn’t a c-drive issue....best Grant 


Ian Park
 

If the prop shaft alternator/ Vetus drive is increasing speed with revs then the issue is clearly after that. I have no experience of the mechanics of the C Drive, but I understand it is heftily engineered. 

l presume you have the original prop and my first guess would back up your idea that maybe the shaft key has failed so most of the idling grip is being produced by the propellor nut, but the extra torque is providing slippage. 

have you tried very gradually increasing speed forward to see if very gradual torque allows the nut to hold the friction. If you get some increase in speed then it would seem to be the prop slipping. 

good luck

ian
Ocean Hobo SN96


Brent Cameron
 

I had a similar issue with my old Yanmar. Like you, it happened after I noticed that the shift cable was binding and I had replaced it. I initially had no issues but got stuck out from the marina sand had to sail it in to my slip with no drive one evening. After some diagnosis, I found I had reverse but not forward.  I then (with the engine off) put the transmission in forward and swam down and I could spin the prop. Did the same in reverse and couldn’t budge it. For me it was a clutch plate, one side was completely worn off so the metal clutch rotor disk was spinning on the clutch wear surface.   I replaced the clutch disk and noticed that when I replaced the cable, I had somehow buggered up the adjustment so that it wasn’t fully engaged in forward and was slipping slightly under load. The manuals were completely unhelpful but I adjusted the cable so I couldn’t budge it by turning the prop in forward or reverse and it was still turning completely freely in neutral. The difference was measured in fractions of a turn on the cable adjustment. I suspect you have the same issue and you will go through another clutch soon if you don’t find it.   Of course if it is the key, you will likely be able to turn it in either direction when engaged in forward or reverse. I haven’t ever seen a key sliced in two though. Do you have a folding prop?  Could it be that it isn’t swing out?  

Brent

On Sep 18, 2020, 7:34 AM -0400, Grant Starling via groups.io , wrote:
I have lost drive on my Santorin.  It started when I replaced the morse throttle/gear selector and at first I thought it was bad cable adjustment meaning my gearbox clutch not engaging properly.  

Basically the problem is as follows.  I start the engine, select gear, when I apply power to accelerate, there is no increase in thrust from the propellor beyond that which I get idling in gear.  So I can move the boat around at idling speed in forward revers, but no thrust or increase in motion even at full revs.

So after adjusting the cable to ensure proper adjustment and still getting no joy, I looked secondly to the gearbox clutch as being the issue.  I thought at 30 years old its probably slipping and needed replacement.  So I rebuilt the gearbox with brand new clutch, bearings and seals.

Reinstalled it this morning.  Same problem is still there.....no drive.

The c-drive seems to be spinning up fine when I increase throttle, it increases in speed.  I can turn the c-drive by hand and it seem smooth and turns easy.  Put my GoPro on a pole and checked the propellor under-water, just to check there was no debris on it....it seems to be spinning fine.

So short of the propellor slipping on the prop-shaft, I am out of ideas?  

Has anyone had a similar issue?  What are the chances of the prop shearing it’s key and spinning on the shaft?  Sincerely hope this isn’t a c-drive issue....best Grant 

--
Brent Cameron

Future Amel Owner & Amel Owner Registry Moderator

Oro-Medonte, Ontario, Canada


Craig Briggs
 

Just guessing, but have you tried totally disconnecting the cable from the transmission shift lever and shifting it by hand, thus absolutely eliminating adjustment as even a remote possibility?
Also, you say you can see the prop spinning with your GoPro - can you also observe the prop spinning faster when you accelerate (as you have observed the C-drive spinning faster when you accelerate? That might isolate your diagnosis.
Keep us posted on this intriguing mystery!
Ctaig - SN68 Sangaris, Tropic Isle Harbor, FL


Dennis Johns
 

Your Santorin has a different gearbox than my Maramu but I know when I had my clutches replaced the mechanic was very careful in making sure the thrust washer was the proper thickness.  He actually took the time to fabricate one in his shop.  Do you know if the thrust washer was replaced?

Dennis Johns
Libertad
Maramu 121

On Fri, Sep 18, 2020 at 7:52 AM Craig Briggs via groups.io <sangaris=aol.com@groups.io> wrote:
Just guessing, but have you tried totally disconnecting the cable from the transmission shift lever and shifting it by hand, thus absolutely eliminating adjustment as even a remote possibility?
Also, you say you can see the prop spinning with your GoPro - can you also observe the prop spinning faster when you accelerate (as you have observed the C-drive spinning faster when you accelerate? That might isolate your diagnosis.
Keep us posted on this intriguing mystery!
Ctaig - SN68 Sangaris, Tropic Isle Harbor, FL


Grant Starling
 

Thanks for all the responses gents...appreciated!

To answer all your suggestions.  It’s difficult to tell if I increase speed slowly whether it makes a difference.  It’s not obvious but I think it may do slightly.  At this point a prop-shaft key failure would be a good outcome, but somehow I doubt that is the issue....but until I can dive on it and test this by hand, I won’t not be able to tell for sure.  Though of course will need to do so.  To answer another question, I have the standard prop.  I did place my GoPro underwater and run the engine, and the prop does seem too increase in speed....though hard to tell if it’s slipping on camera.

Bad cable adjustment is what I thought lead to the first failure, hence me rebuilding the gearbox (Hurth HBW 250).  I definitely didn’t have this right when I initially installed the new control cables as I lost reverse due to it not engaging properly and had to adjust it again.  After that it worked fine for one outing and then I lost drive completely.  After that I figured out I had probably burnt out the clutch, stripped the box and rebuilt it with the official rebuild kit, new thrust washers, plates, shims, seals, and I bought and installed a new bearing kit at the same time for good measure.

So I fully expected everything to work perfectly after the install.  I carefully adjusted the cable this time to ensure proper engagement.  When I failed to get drive again, I completely took the cable off and shifted by hand, still nothing.

I feel I did a good job of the gearbox rebuild, measuring free-play and backslap, and installing the correct shims, thrust washers and components, so I am fairly confident it now isn’t the gearbox...but who knows?  Stumped...LOL.

I don’t think it is the c-drive, that is moving smoothly by hand as I think it should.  So it comes back to the prop or the gearbox.  I guess I’d better go and buy some dive gear and get down below on the prop!  BTW in England the water is not welcoming, so I will need a wetsuit...unlike some of you guys in those lovely warm waters down south!

G.


INDIGOJOE
 

Hi ! 
      I have had a similar issue , if your engine rpm doesn’t increase than it’s a simple cable adjustment , if you can increase your rpm on your engine but prop doesn’t spin , then you have drive train / sail drive  issue . Those are my thoughts . Sounds like a simple cable issue though , some times these things get bent . Best of luck . 
Joe Sciarrino 
Indigo


On Sep 18, 2020, at 8:09 AM, Ian Park <parkianj@...> wrote:



If the prop shaft alternator/ Vetus drive is increasing speed with revs then the issue is clearly after that. I have no experience of the mechanics of the C Drive, but I understand it is heftily engineered. 

l presume you have the original prop and my first guess would back up your idea that maybe the shaft key has failed so most of the idling grip is being produced by the propellor nut, but the extra torque is providing slippage. 

have you tried very gradually increasing speed forward to see if very gradual torque allows the nut to hold the friction. If you get some increase in speed then it would seem to be the prop slipping. 

good luck

ian
Ocean Hobo SN96


Grant Starling
 

Ok, so I think I have got to the bottom of the issue.  It’s the cable adjustment.  Seems obvious now.  I disconnected the cable and shifted the box by hand, loads of drive.  So I am going to have to order and fit a new shifter cable and the original style terminator as I had to cut this cable down slightly to fit a non-standard terminator which is now where I realise the whole problem started.  Basically stick to the original terminator fitting when replacing cables...

I will confirm finally once fitted and fully sorted.  Grant


Brent Cameron
 

I was pretty sure it had to be the cable. Glad you didn’t have to go into the water to sort it. Good luck!  

Brent

On Sep 21, 2020, 5:05 AM -0400, Grant Starling via groups.io <grantstarling@...>, wrote:
Ok, so I think I have got to the bottom of the issue.  It’s the cable adjustment.  Seems obvious now.  I disconnected the cable and shifted the box by hand, loads of drive.  So I am going to have to order and fit a new shifter cable and the original style terminator as I had to cut this cable down slightly to fit a non-standard terminator which is now where I realise the whole problem started.  Basically stick to the original terminator fitting when replacing cables...

I will confirm finally once fitted and fully sorted.  Grant

--
Brent Cameron

Future Amel Owner & Amel Owner Registry Moderator

Oro-Medonte, Ontario, Canada