Saildrive

[VicS]

There is, almost certainly, a third seal on the input shaft as I mentioned above, which will also be involved in this pressure/vacuum generation but it's an oil seal rather than a water seal. I'm not sure where the second water seal is situated.

Richard

Not st the bottom end , I'm sure there be more seals in the top end other wise the oil would leak out .

I dont undersatand why you are debating this
If you look at the parts diagrams and lists you will see what seals there are.
The VP and Yanmar sail drives I have looked at have a pair of seals, back to back, around the propshaft and a single oil seal around the input shaft.

For example
#15 in a VP 130 lower gearbox


#6 in a VP 130 upper gear box


#11 in a Yanmar SD20 lower gear box
(#13 is a spacer)


#14 in a Yanmar SD20 upper gearbox

 

[sailaboutvic]

Vics there no debute on my part I sure Richard right there are other seals else where in the saildrive .
I not strip the top part of a sail drive ,so I have no idea whats seals are in that part .

I think what Richard and I are both comments on was Moody posting where he said there was two water seals and a oil seal , on the bottom end of the sail drive , has your posting shown there only two , one water and one oil , now for any one who not done this job before and stripping the bottom end for the first time ,
Reading that can be confusing ,
I know this because I have personally had to do that job in pass years six times.
Twice this year .
So to clear thing up for once and for all on the bottom end of a 120 and 130 saildrive there is only two seal .

 

[VicS]

Vics there no debute on my part I sure Richard right there are other seals else where in the saildrive .
I not strip the top part of a sail drive ,so I have no idea whats seals are in that part .
.
..
So to clear thing up for once and for all on the bottom end of a 120 and 130 saildrive there is only two seal .

That's right two seals back to back in the lower gearbox

One seal on the input shaft in the top box

https://j109.org/docs/yanmar-sd20-saildrive-parts-catalog.pdf

Only just stumbled on the Yanmar Sail Drive Service Manual which may be of interest / use to someone.
https://www.yanmaritalia.it/wp-content/uploads/2015/02/SD203031.pdf

 

[RichardS]

I dont undersatand why you are debating this
If you look at the parts diagrams and lists you will see what seals there are.
The VP and Yanmar sail drives I have looked at have a pair of seals, back to back, around the propshaft and a single oil seal around the input shaft.

For example
#15 in a VP 130 lower gearbox
View attachment 99292

#6 in a VP 130 upper gear box
View attachment 99291

#11 in a Yanmar SD20 lower gear box
(#13 is a spacer)
View attachment 99294

#14 in a Yanmar SD20 upper gearbox
View attachment 99293

No debate occurring and no diagrams needed. What I don't know about this stuff can be written on the back of a postage stamp.

It's not Vic or me that raised the second water seal issue.

Richard

 

[PabloPicasso]

If the oil is above the fill mark Will it cause a problem, blow a seal, leak out into the bilge?

 

[sailaboutvic]

If the oil is above the fill mark Will it cause a problem, blow a seal, leak out into the bilge?

If you got oil in the bilge you must have a leak in a top part of the box , top seal

 

[RichardS]

If the oil is above the fill mark Will it cause a problem, blow a seal, leak out into the bilge?

It is believed by some or many that filling the saildrive to the max mark, or above, will tend to encourage water ingress past the lower shaft seals.

As there is no downside, many, including me, fill their saildrives only to the min mark.

Richard

 

[differentroads]

I dont undersatand why you are debating this...

Thanks for sharing the SD20 manual. I've replaced the lower leg seals a few times but didn't have the 'official' service manual.
Got to love how specific the Yanmar service manuals are, even specifying the three different types of hammer required for disassembling the upper parts! ?

 

[peter gibbs]

Oil level on the S120 gearbox is reasonably exacting but not excessively. The general principle with oil served engineering enclosures is that marginally under min level is not lethal - sufficient is circulated to perform the function. Running for some time healed is more critical. However, overfilling by a margin, not a few drops, has the potential to stress seals and is to be avoided. If topping the gearbox has resulted in a significant overfill - oil drops down slowly and this is all too easy to happen - then it is best to use a clean piece of plastic pipe and withdraw a little to bring the level down. Remember on the VOLVO, the correct reading is when the dipstick is resting in the hole, not when it is screwed down.

PWG

 

[Skylark]

If the oil is above the fill mark Will it cause a problem, blow a seal, leak out into the bilge?

In 2009 Yanmar issued a Global Technical Bulletin changing the dipstick to one 14.5mm longer to reduce oil capacity of the SD50 saildrive.

The GTB opened with “From warranty analysis, we have found a number of complaints regarding oil leakage at the input shaft or where the oil was emulsified. We found that if our current oil level is slightly exceeded, the inside pressure of the SD50 May exceed the proof leakage pressure for the oil seal. This can cause oil leakage at the input shaft during running and it could suck water from the oil seal on the propeller shaft as well”

It went on to say “In order to obtain a lower oil pressure inside the drive, the max oil level has been changed”

I found this after a Google search some years ago as I have an SD50. It’s probably worth doing a search to see what, if any, info is available on-line specific to your saildrive.

 

[RichardS]

In 2009 Yanmar issued a Global Technical Bulletin changing the dipstick to one 14.5mm longer to reduce oil capacity of the SD50 saildrive.

The GTB opened with “From warranty analysis, we have found a number of complaints regarding oil leakage at the input shaft or where the oil was emulsified. We found that if our current oil level is slightly exceeded, the inside pressure of the SD50 May exceed the proof leakage pressure for the oil seal. This can cause oil leakage at the input shaft during running and it could suck water from the oil seal on the propeller shaft as well”

It went on to say “In order to obtain a lower oil pressure inside the drive, the max oil level has been changed”

I found this after a Google search some years ago as I have an SD50. It’s probably worth doing a search to see what, if any, info is available on-line specific to your saildrive.

Indeed. See posts #21 and #47, amongst others.

Richard