Storm Dragon
Member
The ST4000 on my yacht why does it keep jumping out of drive
Autohelm st4000
- Thread starter Storm Dragon
- Start date
guernseyman
Well-Known Member
....because you haven't got a piece of shock cord binding the clutch lever to the pedestal bracket to maintain the former in the drive position.
jwilson
Well-Known Member
Assuming you have a Mk II wheeldrive. Yes - they all do it. But it's fixable with one allen key.
Look at http://sbo.sailboatowners.com/downloads/Hunter_gen_45963682.pdf and find the exploded diagram. The usual reason is friction between the two plastic rollers (Part 5 on the diagram) and the cams (Part 8) they rotate on. According to Raymarine they just need to be clean - no lubrication. I find a tiny spray of McLube ( NOT OIL OR GREASE ) inside the rings (Part 5) helps it to work. The rest is just adjustment, and wait 3-12 months for it to start jumping out of drive again, at which point you do it again.
Takes about 20 minutes once you get used to doing it. You have to take the wheel off and the drive off the wheel. I take the whole wheel forward in the cockpit, where dropped screws don't fall out of the open transom.
The crude fix is the shockcord that you see on many (maybe even most) boats with these Mk II drives.
Look at http://sbo.sailboatowners.com/downloads/Hunter_gen_45963682.pdf and find the exploded diagram. The usual reason is friction between the two plastic rollers (Part 5 on the diagram) and the cams (Part 8) they rotate on. According to Raymarine they just need to be clean - no lubrication. I find a tiny spray of McLube ( NOT OIL OR GREASE ) inside the rings (Part 5) helps it to work. The rest is just adjustment, and wait 3-12 months for it to start jumping out of drive again, at which point you do it again.
Takes about 20 minutes once you get used to doing it. You have to take the wheel off and the drive off the wheel. I take the whole wheel forward in the cockpit, where dropped screws don't fall out of the open transom.
The crude fix is the shockcord that you see on many (maybe even most) boats with these Mk II drives.
Storm Dragon
Member
Have done as you instructed and the engage lever does not jump out of gear, but have noticed that the motor slips under load and can be heard rotating but the Autohelm does not move, so any suggestions
Mrnotming
Well-Known Member
I seem to have replied to a duplicate thread, have a look Storm Dragon!
jwilson
Well-Known Member
Then you probably need to change the plastic gear wheel that drives the belt. All done with the same allen key, but definitely do this off the boat as you will have to catch the 21 ball bearings as you take apart the drive to get off the gear wheel. The part you need is called a pinion sprocket, and is a push fit on the motor gearbox output shaft. Spare part about £20.
Look at the ST4000 Mk II service manual: it will explain the easiest way to change this - it's not immediately obvious from looking at it, at least it wasn't to me. Online at http://sbo.sailboatowners.com/downloads/Hunter_gen_45963682.pdf
Look at the ST4000 Mk II service manual: it will explain the easiest way to change this - it's not immediately obvious from looking at it, at least it wasn't to me. Online at http://sbo.sailboatowners.com/downloads/Hunter_gen_45963682.pdf
