Originally Posted by Ashley50311
Please forgive my ignorance, people, but although mechanically minded ( I have just installed a new diesel engine in my sailboat - 35 ft Bruce Roberts), I am a complete beginner when it comes to Autohelm ST4000, which came with the boat and was probably installed over 15 years ago. To start with, when the engaging lever is up and I press +10 or - 10 on the control panel, the motor whirrs but the wheel doesn't turn at all, and certainly not the required 10 degrees + or -. This I take to mean that there is a clutch or a belt slipping inside the unit. Any tips before I start to take this thing apart to find the problem? Are there still parts available?....many thanks for your patience people.
Welcome to sailnet. The ST 4000 is no longer manufactured or supported by Raymarine. Look through this thread and you will see that member CaptainDan99 repairs these units and he may have parts as well if you contact him.
As for your question about operation, the clutch lever should be in the DOWN position (I am assuming you have a wheel pilot) and all tension off the wheel lock. In this configuration pushing the + or - 10 should cause the wheel to turn. It won't turn much and it may move in small jerking motions, that is normal. If yo still get the whirring and no movement when the lever is locked down then you probably have a broken gear or belt inside the wheel drive unit. Remove your wheel and there are a few screws on the back of the wheel pilot that allow it to separate into two halves.
Good luck and et us know what you find.