Fuel Tank Sending Units

[cptbill]

On my 2002 Wellcraft 270 Coastal I need to replace the fuel sending unit. Someone before me has already do this with one of those universal ones and there appears to be a pink wire there that's not being used. I was just going to order a 3 wire one from Centroid Products but I thought I'd ask if any one knows what was there originally. Since it's a pre going out of business Wellcraft original parts info is tuff to come by. Also it has Yamaha 250 4 strokes (2006) if that makes any differance

 

[Texasmark]

A 3 wire would be a Potentiometer, a voltage measuring/changing device: 12v, wiper voltage to the hot side of the meter, and ground (batt. -) for both the meter and the plate of the sending unit. Meter doesn't need power supplied like on a 2 wire.

A 2 wire is a Rheostat, a current measuring/changing device. For the 2 wire the meter is supplied power on the hot lead, current through the meter, out the other lead which is wired to the hot side of the sending unit....center terminal for a flange mount, and the case/flange of the sending unit is grounded. Rheostats run something around 230 ohms with the meter R being like 30 ohms...both numbers generally speaking.

 

[cptbill]

Thanks, guess I'll stick with my original plane and get the three wire

 

[dingbat]

Forget the rheostat type sensor. Here is what you want.

https://kus-usa.com/product/sss-ssl-sender/

Follow the length recommendation in the "additional" info. heading.

 

[76SeaRay]

I just ordered and received the KUS-USA one listed above. Mine was two wires but they have a three wire version where the third wire is a low fuel alarm or light wire... These use magnetic reed switches that change the value of the resistance in stepwise fashion so no mechanical potentiometer in them.

 

[Texasmark]

I just ordered and received the KUS-USA one listed above. Mine was two wires but they have a three wire version where the third wire is a low fuel alarm or light wire... These use magnetic reed switches that change the value of the resistance in stepwise fashion so no mechanical potentiometer in them.

Perfect. Gets rid of the mechanical wearing of the wiper on the resistor used with manual units......which eventually breaks a wire of the resistor, or the wiper tip wears off and no longer makes contact.

 

[cptbill]

Ok I'll give that one a try. Thanks folks

 

[76SeaRay]

Their product datasheet is under their support section so a little hard to find....

https://kus-usa.com/wp-content/uploads/2019/01/Product_Data_Sheet_KUS_SSS-SSL.pdf