A18086 ST4000+ Drive motor replacement

[jonelli]

My motor is tired. I’ve found new Raymarine units on eBay for $90 including shipping but I’ve also read an article that explains the motor itself is a Mabuchi motor RS-555SH-TD050112 which can be had for about $5 + shipping. Would need to cut the shaft and re-use old gear and add capacitors. I have no problem with that, but the article describes a source for the motor without any real specifications and the company they referenced has many versions of similar motors so I’m not sure which one exactly it is. I have also found other sources just by searching the web, but again, there are only partial part numbers similar ones that show up.
If anyone could direct me to where I can buy the correct motor so I don’t make a mistake, that would be fantastic.
Here is the reference article from 2015
http://svjohannarose.blogspot.com/2015/12/replacing-burnt-out-wheel-autopilot.html?m=1

Thanks.

 

[Mark Maulden]

Even though I have the skills to do this, I would just pay the $90..Also, there may be some electrical motor rebuild places that may be able to help you with the old one..

 

[jonelli]

@Mark Maulden - I dunno, $80 for a gear and some caps? That's really not a big deal. I'd rather spend the $80 on beer.
Apparently, it is a VERY common motor, so as long as I can find the right one on the first attempt, I'll be happy.

 

[jonelli]

Actually, I think I just figured out my own question. One of their photos clearly shows the only part number on the motor being "RS-555SH" and THAT I can source. Oddly, its available in stock at an audio component supply site.
https://www.parts-express.com/mabuc...MIs738iIbt4QIVAqvsCh1EpAqaEAQYASABEgJZvfD_BwE

 

[Mark Maulden]

Let us know how you make out!

 

[kloudie1]

Indeed.. I'd like to know as well.. I have a 4000+ that works fine but for that price, this motor might be something for the spares box if it fits and the gear fits on the shaft ok.. Thanks for the post , jonelli

 

[mpaule]

I’ve read numerous times that the ST4000 cannot keep up once “significant” weather helm develops, or in significant following seas. If these motors are available from third parties, is there a stronger one that would work better?

 

[MattieJo]

I have a different question on the same unit. While using it the lock on lever on the when begins to reverse itself with each adjustment it makes to the wheel. Often after several small turns it will completely unlock and the wheel is free.

Has anyone had this problem?

 

[jssailem]

@mpaule It sounds like a good idea. Stronger motor is better than weak motor. The engineering is not just in the motor. It is the whole system. The problem is if you try to reengineer the whole unit you will exceed the price point and the purpose the of the unit. That is why the EV200 and 300 exist.

Areas of failure. Belt wears out or breaks. Housing is plastic. The gears in the plastic fail. The screws holding the unit together are into plastic. The plastic breaks around the screws. The whole turning force is focused on a 2" shaft the rotates to turn the rudder. The reason we put big wheels on the shaft to turn it manually is the force of the rudder.

These EV100 units or the earlier ST4000 are great at what they are intended to do. Make small corrections on a balanced boat.

When the wind and seas conspire to move the rudder and turn the boat away from it's true course they are not big enough. There is a reason you see the old Brigs in the movies with two sailors trying to man the helm, even tied to the helm, because it sometimes takes brute force to turn against the sea.

There are reasons for the EV100 to be sold about $1300 and the EV200 in the $2600 range. In the EV200 you are using a hydraulic ram to move a small tiller inserted in the rudder shaft back and forth. Even with this improved engineering, when the seas get angry I prefer to man the helm. And there is always to option of lashing the helm and putting the boat in Heave-to configuration and retreating into the cabin for a rest.

Here is an interesting article by North Sail. https://www.northsails.com/sailing/en/2016/09/how-to-sail-safely-through-a-storm

 

[jonelli]

When my ST4000+ is working properly, it can handle motor sailing and light winds/weather just fine. Heavier situations struggle a bit but I’m still glad to have it.
But, every now and then, my motor wasn’t moving when it should have and the wiring and control are good. If I forced it to move sometimes it would suddenly work for a while. I want to extend the life of my system. I’m still waiting for the new motor to show up. Will let y’all know it’s it goes.

 

[jssailem]

Look forward to your info. It is an idea that interest me.

 

[jonelli]

So far, I received the new motor, and it looks like a match. After inspecting how everything goes together I see no reason to attempt to trim shaft down since it slides all the way into the housing anyway. So, positioning the gear correctly would be the only goal. Maybe I won't be able to put it on all the way without cutting the shaft. I'll need to think about that.
I removed my old motor from the housing and it smelled pretty burnt. I don't know how much of a normal burnt smell it should have, but I'm guessing that it shouldn't.
I had a LOT of trouble trying to get that damn gear off. I still haven't been able to remove it yet, even with a lot of heat. I don't have a small gear puller though. I'm trying to do this with needlenose pliers and screwdrivers.

I went online and did some calculations and determined that the gear has an OD of 10.5mm, and 18 teeth making it a 48DP gear that is about 9mm in height. Searching on Amazon found a lot of RC motor gears that seem to fit those dimensions, so I'm not sure what the OP in that article was talking about having so much trouble finding a gear. I ordered a set of gears which cost more than the motor ($13) because I am impatient and want them in two days.
Stand by for more...

 

[kloudie1]

Saw this idea for a small puller:
https://www.instructables.com/id/Cheap-and-Simple-Gear-Puller/

 

[sailermaned]

I have a different question on the same unit. While using it the lock on lever on the when begins to reverse itself with each adjustment it makes to the wheel. Often after several small turns it will completely unlock and the wheel is free.

Has anyone had this problem?

I have had the same problem from time to time as I use my Wheel Pilot quite often just tightened the screw for lock lever ,it loosens from time to time. Eddie

 

[Skipper]

I wonder if the replacement will be quiet.
My SPX5 motor is loud as (insert your choice of 4-letter description), and has been since new.
So much that I have it set to min response for conditions, and sometimes just turn it off and let the boat track and slither on its own which it does reasonably well in So Cal sea state usually.
My dock mate had a 4000 which is older version, and it was perfectly silent. I guess RM cheaped out later.

 

[jssailem]

The unit RM uses on the EV100 can be quiet. I just needed to tighten the torn headboard screw in the engage lever. Before it rattled like a diamond back about to strike all the time. Now as silent as a church mouse.

 

[seadaddler]

I just replaced with new belt and proper adjustment and now auto works like new and so much quieter and the engage lever stays engaged and when hen sailing heavy with ind works great.
For me a new belt made big improvement

 

[jssailem]

For me a new belt made big improvement

For me too a new belt is always an improvement unless the belt is getting longer.

 

[jonelli]

I wonder if the replacement will be quiet.

Assuming that replacing the original motor with the same motor would be the same, I would say there's no reason it wouldn't be just as quiet as it was. I have no idea if the 4000+ MKII motor (different than the older MKI with black ring) is noisier than what you have.

 

[jssailem]

@jonelli i am hoping your efforts will help us all discover a better solution.