How do I feather the prop?

[jt11791]

New to me boat has a Yanmar 4JH3DTE with a KMH4A gearbox. I went out sailing the other day and after setting sails and killing the engine I heard the Maxprop freewheeling. Actually, I did not recognize the sound at first, so I went below and while looking in the engine room I noticed the shaft turning. I hollered up to the Admiral to put the shifter into gear and she did, no change. In either forward or reverse, the shaft kept turning. The engine was not running, or turning over. This was unexpected! In my past boats, with the engine stopped, putting it into gear stopped the shaft and folded/feathered the prop. What am I missing? The engine needs to be running to engage the clutch? How should I stop the shaft?


I scratched my head a few times, and then as a test, I used a rag to put some friction on the shaft. This slowed it to a stop and once stopped, it was happy to stay that way (prop feathered). The boat handles great under power, no problems in forward or reverse, so I guess all is as it should be. I just don't know the proper procedures yet.

[StuM]

That sounds very strange. What sort of throttle/gear lever? Single or double? Are you sure she actually put it into gear? (i.e not just opened the throttle in neutral?

With a mechanical clutch, there is no way the shaft should turn in gear without the engine turning.

Is the Maxprop fully greased?



Maxprop recommendation:



"The best way to feather the propeller is:•Power at 2 to 3 knots in forward.
•Kill the engine while still engaged in forward."

Edit: Just realised, the KMH4A is hydraulic. (missed the H)
Also from Maxprop:

" With a hydraulic transmission you must shut off the engine while still engaged in forward. The remaining hydraulic pressure will in effect lock the shaft for a few moments, enough for the Max-Prop to feather"

[Mutt]

I have a hydraulic transmission also. I ensure I am doing at least 5 knots then reduce engine rpm and change gear to neutral and shut off engine. If I am doing less than 5 knots the prop shaft will spin. Shifting gear with the engine off will have no effect since the transmission is not pumping any fluid.

[jt11791]

Thanks, I had sort of figured out it was a hydraulic transmission issue. I'll kill it in gear next time.