42: In gear but no thrust - Yanmar engine question

[boatman61]

Had this happen on a Lagoon45S..
Forward gear worked fine on port and stbd engine but reversing only port engine would give power.
Turned out to be the cables.. ask DavidinDubai for details, it was his boat I was delivering.

[Montanan]

Image of an SD60, one can see the multiple discs of the clutch.

[crayiii]

Here's what mine currently looks like.

[a64pilot]

Originally Posted by crayiii

Here's what mine currently looks like.

The clutch packs are in the middle of course, and the two outside gears are I believe forward and reverse, being helical cut, meaning the gears are cut at an angle means there is a sideways force applied to them when the other gear you don’t see drives them, I believe this sideways force compresses the clutch packs and keeps them from slipping, Smart design, takes advantage of an operating principle.
Helical cut gears are often used because they are quiet, straight cut gears often whine. Remember the whirring sound of the old Kawasaki 900? That was straight cut gears. My Suzuki outboard makes that sound too, and while I’ve not had it apart, I’d bet it has straight cut gears.

[Charis2017]

Thanks for all the comments. Further update ... so today after checking the cable and finding they have equal tension, and not yet touching the saildrive, I tested her in the slip again and the Stbd that was giving me trouble was now fully responsive and gave me normal rev and fwd power. It was as if nothing happened. Only difference I noticed this time was maybe a second or two delay on Stbd. But otherwise the thrust seemed to match Port.

[Charis2017]

Originally Posted by crayiii

Was there any issues leading up to this? I'm battling with a noisy SD60 (thread is here http://www.cruisersforum.com/forums/...60-220487.html)

2017 lagoon 42 with under 300 hours.

No, not in some time. And certainly no different sound/noise. Only issue we’ve had was when we sailed her 2 years ago from Annapolis to SF and the props got fouled up with fishing line. That ruined the seals and I had to have them replaced in the yard. But no issue since then.
Good luck.

[boatman61]

Originally Posted by Charis2017

Thanks for all the comments. Further update ... so today after checking the cable and finding they have equal tension, and not yet touching the saildrive, I tested her in the slip again and the Stbd that was giving me trouble was now fully responsive and gave me normal rev and fwd power. It was as if nothing happened. Only difference I noticed this time was maybe a second or two delay on Stbd. But otherwise the thrust seemed to match Port.

Pretty sure thats your problem.. Dave had new cables fitted in Gib and when I moved the boat from Cartagena to Corfu for him this year everything worked great.

[a64pilot]

Well, if it starts acting up again, and I think it will, you can easily confirm its the cable by disconnecting the cable, if it stops slipping with the cable disconnected then that was it.
The cable could make it slip by not allowing it to fully engage, my manual warns against slowly easing into gear, cause of course the clutch is slipping while you ease it in.
Since it’s both directions, I don’t think it’s cable, if its the prop, it will return

[Darksyde]

I had the same issue on my 450

its the clutch

There is a Service Part from Yanmar

Now I hear a really cluck when engaging forward and reverse and the
problem with less thrust is gone

M