42: In gear but no thrust - Yanmar engine question

[Charis2017]

Hi, I’m wondering if there are ideas out there on my engine problem.

When I put Stbd into gear (either fwd or rev) it engages, but I don’t get much power. Very little wash from the prop, where the Port power is normal.

RPM on Stbd and port side seem the same, but there’s a clear difference in the power/thrust. Engines sound the same. Checked the props below, both sides, and nothing appears wrong, no fouled prop, and they respond the same to touch. I checked the gear cable and Stbd seems no different than Port in both fwd and rev. Fluid looks good. (I had changed fuel and oil filters a few weeks ago).

Yanmar engine. My Saildrive is an SD60

I checked YouTube for any maintenance videos and I’ve had no luck finding something on point.

Thanks for any and all ideas!
Noah

[a64pilot]

Since it’s both forward and reverse,
I think some if not all sail drive props have a rubber clutch or bushing similar to outboard props. Could it be this?
Sorry I don’t have and have never had a saildrive so I’m not certain, but if there is indeed a rubber hub and if it’s spun that would be better than a transmission.
I think but am not sure that the SD60 has multi plate wet clutches, and these don’t often slip, plus for both to slip would I think be very rare.

[Wotname]

I think A64 is on the money but like him , I can't be certain - not knowing much about SD props.

If the water is warm enough and both props rotate the same way, you could swap the props around for further fault analysis.

[a64pilot]

We need someone who knows saildrives

[DK2]

If this was a SD50 I’d say the come clutch was slipping, they are known for it.

[AndyinAbudhabi]

Agree with DK2. I have SD50s and have had to repair both saildrives.
I think the SD60s have a different clutch setup. Plate instead of cone.

[Greg Mason]

Is is possible that if it is a clutch there is a fluid pressure issue? Both forward and reverse is the key.

[Moontide]

Props on Saildrives have rubber hubs that are designed to spin free if you hit something, instead of taking out the Saildrive. Same approach as outboard props (not the old ones with shear pins). I spun one once and the symptoms were the same.



My guess is that you "spun" a prop. Means pulling it and either sending it to manufacturer for repair. Don't know if prop shops do these repairs or not.



If your in an out of the way spot I have heard of people taking epoxy and basically gluing the hub back together. Then it is more gentle use for maneuvering than for full thrust underway.



Bill

[Charis2017]

Thanks all. Appreciate the feedback and consensus on the saildrive, which is entirely new to me. Haven’t found anything on the SD60, but I’ve got someone coming by and hopefully he can help me resolve the issue.

[a64pilot]

Originally Posted by Greg Mason

Is is possible that if it is a clutch there is a fluid pressure issue? Both forward and reverse is the key.

If it’s like my KBW20 it uses engine torque to squeeze the clutch plates together. So you get an easy to move lever as in neutral and idle there is no torque, but when in gear the harder you run the engine, the more the clutch is pressed together to increase friction.
It’s such a simple system, I’d be surprised if they abandoned it.
But I agree both forward and reverse is key to understanding the issue, even cone equipped transmissions don’t slip in both directions, I don’t think, but as I have never had a cone type transmission or a sail drive, it’s all theory to me, no experience.

I’d bet if it’s the prop hub that most any good prop shop can replace it, and for not a lot of money. It has to be a somewhat common problem?

[Moontide]

If you feel like going swiming there is an easy test. Know it works on the SD50 and below but have not tried it on a 60.


Put the engine in gear then dive the boat. Try turning the prop. It should only turn one way. If it passes that test (turns one way but not the other) then shift into reverse and try again.


If it turns both ways in either gear (or both) will mean the hub is "spun". Depending on what props you have it can either be easy or a pain to remove in the water.


Good luck.
Bill

[a64pilot]

There is a picture of the internals of an SD60 on the SD60 goes clunk thread. It strongly appears to me that the helical cut gears on either side of the clutch packs do indeed force them together harder the more torque applied to those gears, it doesn’t appear to be hydraulics system

[Montanan]

Yanmar Saildrive Type SD60
Reduction gear system: Constant mesh gear with wet type multi-disc clutch.

The SD50 has a cone type clutch.

[Wavehiker]

Not quite the same problem as you but when I put my SD60 in gear nothing happened for 5-10 seconds then it grabbed. Yanmar sent someone to my boat to remove the top of the saildrive and shipped to somewhere in Florida. It was reinstalled within a week. Never have had a problem since. Clearly there was some kind of defect. My SD60 was installed mid 2015. Failed with only 130 hours on it.

[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.