Yanmar Saildrive Problem Engaging Drive

[Trident]

After an oil change on a perfectly performing SD20 (albeit old) it was difficult to get in to drive though fine in reverse. A manual touch of the finger to the gear shift on the leg and it instantly engaged. No hard push, just a couple of mm to get it to engage and then its fine.

I drained a little oil on reading advice about the directions from Yanmar having changed (basically to fill a little less than the manual says) just in case there was some hydraulic lock effect in place. Made no difference

I then adjusted the cable out a few mm and made no difference and then tried the other way and made no difference and then out as far as it will go and again made no difference. It engages on its own (engine on and a quick push in to gear as recommended with a dog clutch) about 50% of the time - sometimes 4 or 5 times in a row and then not at all until I again manually push it in.

I can't see that there is any more I can do with the cable length (having tried 2mm longer , about 5mm longer and to maximum length and also just for the hell of it a bit shorter too in case the extra length was the problem and allowing deflection)

My Yanmar dealer says take it for a good blast and loosen everything up - which is fine if you don't have to manoeuvre a 50 foot cat around small marine and through a lock with 6 inches each side where you need instant fine control of the boat.

Does anyone have any suggestions as to what I try next please?

 

[TiggerToo]

Check that the oil used is an appropriate one for the sail drive. They are really quite sensitive to the incorrect grade: the symptom you describe is exactly the sort of thing you'd expect from using the incorrect oil.

An oil change (twice!) may result in a resumption of "Perfect Performance"

 

[Trident]

It said 80/90 hypoid gear oil on the bottle which is what was specified but there wasn’t enough so it was mixed with about half a litre of a different make of 80/90 gear oil. If they are hyper sensitive then I’ll try another change and see if it helps - this time with Yanmar branded oil to be safe. It makes sense as it worked fine despite 6 month winter break on the way to dry out for the oil change but immediately after was acting up - I assumed the correct weight of oil would be fine from any brand but who knows (possible you do )

 

[TiggerToo]

I can imagine that mixing the two oils may be have been the problem. Although the grade are nominally the same, I can imagine the combination may have altered some parameters that lead to "sticking".

I experienced the same last time I did a change: I thought I was saving material, in the end I wasted more.