Happy Holidays to All. I am the...

[Mia_Bambina]

Happy Holidays to All. I am the proud owner of a 1999 SR Sundancer 50, I need help finding a Remote Throttle Sensor Control Unit, The Part Numbers in the label shows (WM-531-131684 / 14L0132 / 163091A), I can find nothing close, other than WM531.

Thanks To All

[wingless]

Please post an image of the part.

[Alumofcu]

I've got the same boat but 1998 so I imagine we'll be sharing a lot of info.

[Mia_Bambina]

Sounds Great

[Mia_Bambina]

I Just put a few photos of the sensor, appreciate any help
is greatly appreciated

[wingless]

Thanks for the image.

Those look like hydraulic to rotary actuators driving a stacked resistor pack.

Assuming one is still good, then cannot that part be measured to locate an equivalent part?

[wingless]

Assuming the problem is the stacked resistor pack, my guess is a dead spot on part of the rotation.

That dead spot is probably the most used rotation location, over decades of usage.

The first thing I would try is cleaning and possibly lubrication of the problematic parts.

The next thing is that those parts probably work over 270 degrees, but the application only uses 90 degrees. If so, then what happens if the mechanics are modified to work on an unused section of the resistor?

If the application is not happy with the incorrect resistance,even though it doesn't have a dead spot, then can the new section resistance be modified?

If the new section resistance is too low, then add a permanent series resistance.

If the new section resistance is too high then add a permanent parallel resistance.

[Mia_Bambina]

I really don't know, all I know is that they convert the mechanical physical throttle movement to an electronic signal that is sent to the engine computer,

When I Google it I found this from Curtiss-Wright:
The WM-531 Shaft Hand Control is built for a range of
applications. The unit is designed for remote installation
and mechanical interface with a throttle position sensor. It is
infinitely variable between 0 and 54 degrees, with applicable
uses that include engine RPM.
Thanks

[wingless]

The existing mechanism already permits relocation of the resistor pack 45 degrees, so they apparently already planned for this wear problem.

If resistor cleaning does work, then repositioning onto an unused section may be accepted by the engine.

[wingless]

Has a multimeter been used to measure the resistance versus rotation for each part, to quantify which is problematic and at which rotation?

[Mia_Bambina]

That sounds very promising, Thank You, I have been able to navigate my boat by using the Synchronize switch with the Starboard engine. One more Question, If cleaning the sensor does not work and I have to relocate position, do I have to do the relocation process to both Sensors so they match? Again Thanks

[Mia_Bambina]

I haven't done the Multimeter test but will do so tomorrow and let you know. I am sending you a copy of the info I found on this Sensor

[wingless]

You're welcome.

Don't know about needing to do both.

Thanks for the data sheet. Are you certain this is your part? The image is similar but different.

That part won't tolerate mounting rotation because of the 54 degree operating range.

This is a Hall Effect device, not a variable resistor.

There is nothing to wear. The part is sealed.

I would start external to that part, looking at electrical connections and looking at the electronic stimulation for this Hall Effect device.

The properly functioning device either has a DC or an AC stimulation current that generates a Hall Effect voltage, used by the electronics.

A multimeter could measure that stimulation current on both parts and the Hall Effect voltage on both parts, at the part and at the engine, it should be the same.

[wingless]

The data sheet shows that Hall Effect device to be a fully self contained part, requiring only DC voltage power and outputting a DC voltage with linear proportion to rotation and to the input DC voltage.

As such, testing that part is EASY.

Verify DC supply voltage on both parts, probably 12VDC.

Verify linear output voltage, proportional to rotation on both devices.

[wingless]

Any progress on problem diagnosis?

[Mia_Bambina]

Sorry to inform, i was not able to work on it over the weekend, I am hoping to dedicate time on Thursday the 26th , But Thanks for Asking, Merry Christmas

[Mia_Bambina]

Sorry, I forgot to mention, a couple of things,
First, on the Data Sheet it looks similar but it does have the entire sequence of numbers.
Second, a couple of weeks ago i exchange the connectors to test and the Error moved with the connection to the Starboard engine computer along with the malfunction itself, I return to the original position.
Again Thanks for listening.

[wingless]

Merry Christmas to you also.

Am I correct with understanding that the port / starboard parts were swapped AND the error code followed the part NOT the location?

FWIW, that is an EXCELLENT diagnostic method, one of my favorites...

If the fault is following the part, then it sounds like a bad part.

My guess from examining the data sheet is that the electronics are screwed onto the mechanics.

If that part is already bad, then I would attempt careful disassembly for a hopeful repair. It may be that there is internal dendritic corrosion killing functionality that could be resolved by appropriate cleaning, as one example of a user-effected repair.

Otherwise, that part looks expensive to replace.

[Mia_Bambina]

Thanks Again, I will try cleaning this part this weekend, but I have a felling I am going to end up buying a replacement, the problem is I don't know where to purchase it as I cant find it anywhere.

[wingless]

Have you spoken to the manufacturer, Curtis Wright Williams Controls, (503) 684-8600 ?

It looks like they are on holiday now.