Autohelm 4000 Belt Adjustment?

[karista]

My Autohelm 4000 lever started popping up. No, its not the roll pin that is broken. I have read all the comments, and finally removed the wheel cover, the original belt was chewed up, so I ordered the Gates belt that was recommended on one of the forum posts. This belt is slightly longer and not as wide, it did NOT work, so that was money and time wasted. I then bought the original belt, somewhat pricey, I installed it, however the lever still pops up. It appear that the eccentric lever action does not provide enough engagement. Is there a way to adjust this belt to tighten it? The drawing I have shows a adjustment locknut, however it is not a locknut but rather a sleeve with 2 small holes. This would require a special tool to loosen this sleeve. Has anyone adjusted the belt? If so, how was it done?

[Ken Juul]

If I remember correctly there are instructions on how to adjust the tension in the Autopilot manual.  If you don't have a copy you should be able to down load one from the RM web site.

[karista]

If I remember correctly there are instructions on how to adjust the tension in the Autopilot manual.  If you don't have a copy you should be able to down load one from the RM web site.

The manual states "return drive unit to the repair center if it slips"! I called Rymarine and they were not very helpful, they no longer provide parts or service for this early version unit. They recommended that I upgrade to the current Model!

[Hawk]

Try a search on the Main Message board using "autopilot". Also check out this thread dealing with ratcheting of the belt and how to adjust it......might help you.
http://c34.org/bbs/index.php/topic,2364.0.html

Hawk

[karista]

Hawk
I had checked your referenced discussion, however it simply referenced the adjustment but not how its actually performed. Yes, there is a cover that must be removed to get access to the locknut, however when removed there is no locknut there, it is a small sleeve with 2 small holes. I assume it maybe threaded, however to loosen it, one would require a very specialized tool.
I would like to hear from someone that actually has adjusted the belt.

[Wayne]

On mine there was do removal or disassembly.  On the back of the ring that attaches to the wheel there is a plastic 'finger nut' type knob  that is locked into place by an allen wrench head screw in its middle.  Loosen allen head slightly, turn knob a couple of clicks, re tighten allen screw.  There are some '+' and '-' signs molded into the plastic ring.  But the important point is that everything is done from the outside.

[Hawk]

Karista,
I did adjust mine to silence the racheting. Follow Wayne's suggestion as the adjuster is oblong shaped to tighten tension on the belt.

Hawk

[karista]

On mine there was do removal or disassembly.  On the back of the ring that attaches to the wheel there is a plastic 'finger nut' type knob  that is locked into place by an allen wrench head screw in its middle.  Loosen allen head slightly, turn knob a couple of clicks, re tighten allen screw.  There are some '+' and '-' signs molded into the plastic ring.  But the important point is that everything is done from the outside.

You must have a newer model, mine is the original Autohelm 4000, there is no allen head screw or '+' and '-' signs. Mu model has the compass in the control head and most likely was the first design (1990).
As I stated before, I have the drawings, they show a adjusting locknut, however it turns out it is not a locknut but rather a sleeve with 2 small holes, which I assume are used with a special tool to loosen/tighten it. It may have been purposely designed this way to make it impossible for a user to adjust the belt. Stu was right in a earlier post were he called this model a TOY, I agree, it is cheapily made and poorly designed.

[Stu Jackson]

Wayne, I didn't say that, but if I did, then I was quoting Steve, 'cuz I don't have one.  And you can quote me on that!  There are some folks who like theirs, and Steve reported his worked for his entire cruise once he fixed it, although I believe it was a newer unit.

[Ken Juul]

I did set the tension on my old 4000 drive unit, it was probably 8 years ago, but I don't remember it being that hard.  It may have been a slightly newer model, but it was still the black case 4000 drive unit.  The belt tension adjustment is done by loosening a locknut and then turning an eccentric drum that is part of the the tension roller assembly.  I think the part you are describing with the two holes is the eccentric.  There are a bunch of old posts that come up if you google st4000 belt tension, of the few that are useful, one describes removing a cover to get at the locknut.  One describes this cover as being part of the tension roller, another says it is external.  Get your magnifing glass out and find the cover that hides the locknut.  You can probably use a pair of snap ring pliers or McGiver something to fit in the small holes to rotate the excentric.  If you can't figure it out, since you have it appart, you may want to stop buy a marine electronics shop that has been in business for several years (long enough to have worked on the 4000) and ask them.  Most realize the paperwork to charge for the 5 minutes work isn't worth it and will be happy to help (times are tough, tip them).  Others like RM will try to sell you a new unit....I'd walk away from them. 

[Hawk]

Mine is 1990 model same as yours it appears. Its not a toy and not cheaply made in my experience. Oh sure I have dismantled the wheel drive twice to deal with belt tension issues and several dismantlings of the control box to reattach wires and power BUT it keeps on ticking...so have patience. And every now and then when sailing north in a quartering sea it will go "crazy Ivan" on you. Thats when I just turn it off.

Hawk

[Ken Juul]

If the link doesn't work look in the "wacky autopilot" article in the Electronics topic of the Wiki.  About half way down the page is a picture and explaination of belt tension.  The picture is of the ST4000 (black case), hopefully it will help.

http://www.c34.org/wiki/index.php?title=Wacky_Autopilots