Volvo Penta S120C Workshop Manual

[NoTies]

The manual is 80mB so I'm going to send from my work server in a couple of hours. It'll gobble up half my mobile plan otherwise.

[jimbunyard]

There is another option to try that may give you some information before you attempt to separate the engine from the gear. If you take the oil cap of the sail drive, the shaft in the center (item 23 in the 2nd picture) is the drive shaft that actually turns the propeller. You can grip the 1/8" that protrudes past the retaining ring with a pair of vise grips (tight enough to hold but not tight enough to dig into the metal) and use the vise grips to turn the shaft, as shown in the first photo. With the drive engaged, if the input shaft (item 7 in the 2nd picture) splines are good, you should only be able to rotate the shaft in one direction. Shifting to the other direction should only allow you to rotate the shaft in the opposite direction. This is a viable test if the cone clutch is working properly; if the box is in gear you're actually trying to turn the engine over by turning the shaft with the vise grips . If you can rotate the shaft in either direction with the gearbox in forward or reverse, there is no connection between the engine and the transmission, and that is your problem.

From your description, the issue lies with either the input shaft splines, the drive plate splines, the lower splines on the intermediate shift shaft (item 23), the splines in the coupler (item 29) or the upper splines in the lower unit drive shaft (item 4). My first guess would be the coupler, because you saw the shaft turning when you ran the gear without the cap, but there could be some residual contact between the splines on the drive plate and input shaft that would spin the gears and make grinding noises but not engage the propeller....

Can you tell anything from where the sound appears to be coming from? Is the grinding coming from around the flywheel or does it seem to be coming from lower down?

The crack in the shift mechanism might indicate that someone made a high rpm shift at some point, and the damage is just now catching up with you.

[NoTies]

Been trying to send the damn manual all morning but at over 80mB it's too big. Any idea how to reduce the size of a PDF or split it into smaller sections?

[jaybird1111]

thank you JimBunyard. See you're in Slidell, close enough to buy you a beer

NoTies, please check your PM

[jaybird1111]

Extremely grateful to NoTies for his kindness in working out a way to send the manual.

I'll be utilising the kind advise of the posters here and post progress.

I also have a friend who is a website manager, and I'll see if I can't get him to host the manual at his site

Thank you.

[jaybird1111]

Can't edit previous post.

I have resampled the PDF to 3.83MB, if anyone is interested. It is working on pc and mac

[jaybird1111]

Link to 4mb manual at Dropbox:

https://www.dropbox.com/s/w25oddyb93...ll%29.pdf?dl=0

[Thumbs Up]

I could use some advice on this topic of volvo 120 saildrives. I have fixed props and my drives make a lot of racket over 6 knots (sailing) so I usually shift them into reverse (astern) to lock the drives. When I go to unlock the drives (shift back to neutral) my port saildrive easily shifts out of gear but my starboard drive gets stuck in reverse. To get it out of reverse I have to start the engine in gear and then it will shift back to neutral. My questions are: why would it lock in reverse and am I damaging it further by sailing with it in gear?

[jaybird1111]

I'm fairly certain that for fixed props, Volvo suggests you leave the gears in neutral. Reverse for folders.

In my Googling for info on my problem I remember finding someone with the same question as you, think it was at YBW? Might want to go there and search 'Volvo 120S Saildrive'

[Thumbs Up]

Thanks, I couldn't find it but I do remember reading a discussion awhile back about it where the person was doing the same thing and had the same problem (had to start the engine in gear to disengage) and had done this for a long time with no problem which was part of my justification for doing it. I just want to know the technical reason why it does this (jams in reverse).

[DougR]

Currently VP is recommending that the saildrive be placed in reverse when sailing with a folding prop, and left in neutral when sailing with a fixed prop. There are a couple of reasons for this..reverse gear will cause the prop shaft to lock thereby allowing the folding prop to fold or feather, hence lower drag. Keeping the drive in neutral while sailing with a fixed prop allows the prop to free wheel, thus providing lower drag than a non-freewheeling prop.

When sailing with a fixed blade prop shifted into reverse, the pressure of the water trying to spin the prop forces the shift cone hard into the shift cup. This pressure is developed by the helix on the shift cone and the helix on the upper verticle shaft. (explained earlier in this thread) The higher the boat speed, the higher the force pushing the cone and cup together. This force can be beneficial when motoring, as the engagement tends to not slip under high throttle loads. As long as the boat has forward motion and the engine isnt running, it can be difficult to get the drive back into neutral. However, when you start the engine the shift cone will now be rotating, and the ecentric motion of the shift shoe in the shift cone groove breaks the "suction" between the shift cone and cup, making it easy to get out of gear.

As to the question of why it only happens on one side and not the other.... its probably a case of slightly different wear, shift shoe adjustment, maybe even shift cable adjustment and drag. It is unlikely that you are doing any damage by sailing with the saildrive in reverse unless you have large three blade fixed props and you are sailing at 10 or 12 knots or more.

DougR

[Thumbs Up]

Thanks for the info, Doug. I believe that I will continue locking the prop this way. The spinning props make a lot of noise and surely contribute to wear and tear as well. As for the drag induced by stopping the prop.... there are actually arguments, I think even Nigel Calder says less drag when the prop is stopped from spinning but I haven't experimented much but my guess is that I lose half a knot of boat speed by stopping the props. Folding and feathering props are out of my price range.

[jaybird1111]

Vis the kindness of my friend, I present two versions of the 120S workshop manual, hosted more or less permanently

Volvo 120S Saildrive manuals: 4mb file http://linkpro.net/files/120SsdriveWorkshopManual.pdf
Volvo 120S Saildrive manuals: 2mb file (optimized for size in Acrobat) http://linkpro.net/files/120SsdriveWSM.pdf

[jaybird1111]

Pulled the engine off the saildrive

And found the splines pretty badly worn, but the torsional dampener plate is DONE.

I'm gonna work with my friend with machine shop contacts and see what we can do about fabricating something similar to the DB Marine conversion kit.

Any further advice, I'm happy to hear it.

Again, thank you all for your help. I hope I can repay your kindness.

Splines:


Dampener:

[DougR]

Glad to hear that the problem is with the damper and splines, and not deeper in the drive....

Without seeing the splines I would suspect that the least expensive and fastest fix would be to replace the damper and be out sailing again.

However if thats not the way you want to go, then a couple of thoughts that might be helpful.

1. The purpose of the rubber element in the damper is to absorb and dissipate the torsional vibrations found in the crankshaft and prevent them from reaching the gear box where they could cause gear rattle and perhaps longer term gear damage. If you go with a hex shaft arrangement such as seen on the internet you should try to include the remains of the existing damper in the solution. This will maintain the torsional element that currently exists.

2. The rubber element also is part of the electrical isolation system that prevents continuity between the engine and saildrive. By isolating the drive from the engine and vessel ground system there is a significantly reduced chance of experiencing corrosion on the saildrive.

3. In conjunction with the rubber drive element, you probably noticed the plastic islolation bushings surrounding the flywheel coverplate fastners where the cover plate is attached to the bellhousing. These bushings and washers, as well as the large gasket and centering ring need to be re-assembled carefully to maintain the electrical isolation. Dont connect anything between the engine and saildrive that could electrically connect the two.

Regards,
DougR