I replaced the drive belt on my Autohelm St4000 got the belt here
http://shop.polybelt.com/Belt-for-ST4000-Autohelm-Raymarine-Autopilot-BAT750AUTOST4000.htm
The belt skips when used hard. The old one didn't. I noticed the cogs are not square at the end sort of m shaped where it fits into the drive pulleys.
Where have others got replacment belts that they are happy with?
Jim
Jim : Get ahold of the Gates Belt Co and give them the # from the old belt.
I'll bet they can help you!! A thought
Jim, I replaced my belt this spring fromPolytech and it works great. One thing I noticed was that one of my rollers was frozen. Here is the address for the autohelm service manual. Hope it helps. http://www.ganssle.com/jack/st4000.pdf
Jerry
I changed back to my old belt. It looked OK but I have 5 seasons on it (don't know if the PO ever change it) and I use it a lot. Well my old belt doesn't slip. After doing some searching here I see that the belt tension is adjustable and having too much or too little will cause the belt to slip. It did seem a little tighter. So I don't think that anything was wrong with the new belt. Now that I have a new belt and see how simple it is to change I'll just keep using the old belt till it shows a problem.
FWIW I have tongue depressors (from a craft store) that I use as mixing sticks. They worked well to gently pry the halfs of the autopilot apart.
Thanks for the replies.
Jim