[CA] [CA11] M81136 slipping in rough seas

[scottotheforest]

Season 3 with my Hunter 410 and its ST4000 with chain drive to a rotary drive M81136.

All good until this summer, when it started to slip momentarily (awful sound) in rough seas mostly in following, or rear quartering) when the rudder is being pushed around.

The chain had some slack until today when I loosened the mounting bolts slid the M81136 on its mounting slots to one side until it was 'just tight', as per the install PDF I later found online.

I also tightened the 2 Allen screws on the M81136 shaft with the chain gear as well as the 2 on the big sprocket attached to the Edson wheel rack & pinion. None of the 4 Allen screws seemed loose, but I got a bit of extra tightness with the small Allen's wrench.

Sprocket alignment looks good to the eye.

I also removed the 2 hex bolts to open the M81136 (black cover) but with the wires still connected (power off!) I didn't have enough slack to pull the cover compelety off- but honestly, it was just a shot in the dark hoping to see something obvious, which I didn't, not really knowing what I was looking for!

Am I ready to try it again on the water? Course adjustments at the dock now seem fine with the just tight chain, but they would have before when the chain had some slack in it too, so I don't take comfort there.

Any advice or other things to look for appreciated.

[Chuck - Raymarine - Moderator]

Welcome to the Raymarine Forum Scott,

Unless the sprockets were rotating on the shafts, then then reported symptom would typically indicate a problem with the rotary drive unit's clutch necessitating that the drive unit be sent to Raymarine’s Product Repair Center to be bench checked / serviced.