French Polynesia anchorage: Volvo Penta saildrive S120S-E will not engage forward (cables are ok)

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pedal88

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When reversing the boat in an anchorage yesterday, the boat suddenly did not want to shift into forward.

I have troubleshooted the cables, that are ok, but I have disconnected them and done the rest of the troubleshooting by moving the shifter manually.

When engine is not running:
It is easy to shift the shifter by hand, to forward (shifter rotates counter clockwise from neutral position), neutral and reverse (shifter rotates clockwise from neutral position).

When engine is running:
  • The shifter easily shifts to reverse gear and back to neutral.
  • Some times the shifter physically moves without much force to forward, but there is no «gear shifting sound» and the forward gear is not engaging. When increasing RPMs, gear appears to still be in neutral, and the boat is not moving.
  • Other times the shifter do not want to move to forward position, even when applying moderate force on it.
  • A few times the shifter moves to forward and the forward gear engages. The very few times this have happend during troubleshooting, it seems to only have happend when shifting directly from neutral to forward after starting engine. If shifting once to reverse, it will never shift to forward.

Some info: I have had SAE 80W90 non.synthetic oil as gear oil for the last 30 hours of engine operation. There appears to be leaking some levels of engine oil over to the gear oil as the level have increased slightly, and the oil is definately black and not milky/grey. I replaced the oil with 75W-140 synthetic

I have removed 2 shims from under the adjustment bolt, and there are 4-5 more.

What can be the problem and the cause of it?

How can I continue troubleshooting and/or fix it?

Can I damage anything by removing more shims?

I am at an anchorage in French Polynesia, so dont want to do something that can result in worsening the problem.

PS! The picture is not of my actual shifter, but some pictures I found from a prior thread at the forum, and it looks the same to me

Hope anyone have any ideas! :)
shifter_pic.png
 
I don't understand your use of the word shifter?

There is a little arm on the top of the 'rod' on which the morse cable acts as part of the Saildrive, it moves one way for forward and another way for reverse. You can move the rod and its little arm by hand - and when we lost a morse cable I bodged up a piece of kevlar rope and some blocks so that by pulling the ropes I could shift gear at the helm.

Because I don't understand your use of the word shift and shifter I don't know if the issue is with the controls 'on deck' - where all the morse cables terminate or the controls on the sail drive (or the morse cable in between).

I'm not an expert at all - so if its the controls at the morse cable control - I have no ideas. But others might.

Jonathan
 
Hi and thanks for the answer. I used the word shifter (read someone used it in another post) about the triangular part on the picture in the initial post. The one with 2 bolts and the end fitting for the morse cable in its 3 corners. Maybe its a bit different design at yours engine with a rod instead (?). My understanding is that when this moves, it will move the shift shoe also. Since the problem persists when moving it manually, unfortunately it seems that problems with the controls on deck, or the cables, is not the cause.
 
I think you need to look at the other end of the morse cable as well, where it joins the sail drive. The said drive has a rod protruding out of the top and a short section attached to this rod at right angles, like a little tiller. The morse cable should move this short section back and forth. You may need two people - one to shift the controls on deck and one to observe what is happening at the top of the sail drive. Hopefully when Europe wakes up we have the complete story and be better able to help.

Jonathan
 
Suspect your problem is with the clutch pack as a result of using the incorrect oil. The correct oil for a 120SE is synthetic gear oil API GL-5 SAE 75W-90
 
pedal88 said:
When reversing the boat in an anchorage yesterday, the boat suddenly did not want to shift into forward.

I have troubleshooted the cables, that are ok, but I have disconnected them and done the rest of the troubleshooting by moving the shifter manually.
Click to expand...

You appear to have done the right thing in trying to operate the gear shift locally after disconnecting the control cables and established that the problem lies in the gear box rather than the controls

You might find the workshop manual helpful ( pages 20 et seq describe the gearshift assembly and the adjustment with the shims )
https://www.plaisance-pratique.com/IMG/pdf/VolvoMS2-SD120_manual.pdf

The condition of the oil is of concern. It should remain "clear and bright" but may darken a little . It should not become black.
You dont say what engine you have but I don't think it is possible for engine oil to get into the gearbox.
I suspect water has got in ( via a bad prop shaft seal) and caused some corrosion which is has resulted in the clutch system non operating freely
The correct oil for this version of a 120S drive is as Tranona says GL-5 SAE 75W-90

BTW it has cone clutches not multiple disc clutches as Tranona seems to imply.
 
Last edited:
The blackness in the oil is likely to be from the clutch slipping. Cone clutches do wear and the loss of one motion ie forwards or reverse, is typical - its certainly what happened to me. In my case, and it was another make of box, the repair choice was either a new clutch or shimming the existing one.
That said, the linkage should work normally even if the clutch was worn so maybe more investigation of this area first.
I would be very sure indeed that the problem would not be cured by changing the oil.
 
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