Water tank sending unit 330 Express

[usmm1234]

Anyone familiar with this sending unit? It’s probably original from 2002. Need to find a replacement.

 

[Bayhouse]

See my other post, check the wires to the gauge first. Might even want to check continuity from gauge to sending unit.

 

[usmm1234]

See my other post, check the wires to the gauge first. Might even want to check continuity from gauge to sending unit.

That’s a good idea since I’ve had 2 other broken wires in the harness since I bought the boat. Forward bilge pump switch and hardtop speaker wire.

 

[wspitler]

Easy to check the sending unit. Pull it out and read resistance as you run the slide up and down.

 

[usmm1234]

Easy to check the sending unit. Pull it out and read resistance as you run the slide up and down.

Im not sure how to remove the sender. It does not have the usual 4 or 5 screws holding it down. I assume it screws out, but I dont want to break anything.

 

[seasick]

It might just be a push in fit. Try a little twist and a tug.
May I ask, is your indication an actual level of just a full/empty type of signal.

 

[usmm1234]

It might just be a push in fit. Try a little twist and a tug.
May I ask, is your indication an actual level of just a full/empty type of signal.

It a traditional analog gauge with the needle

 

[seasick]

O, got it. I asked because I did some searching and there are different types of fresh water sensors; Full range like a fuel sender and reed switch which indicate certain defined levels like full and low.

 

[usmm1234]

Okay. You guys like Happy Endings? I crawled back across my gen set to try to remove the sender. I put a pair of channel locks on the square blue cap on the top of the sender. It does screw out. In order to do that. I went to disconnect the none waterproof spade connectors. When I did. They crumbled. They were severely corroded and the wires had a lot of corrosion wicking. I’m going to have to go back in and replace all the wire where the corrosion has gotten between the copper and the insulation (Wicking).
But for the time being. I cut out the connectors and some of the bad wire and reconnected them with waterproof heat shrink butt splices. Boom! My water gauge works perfect.
Ive attached pictures.

 

[jip40]

Okay. You guys like Happy Endings? I crawled back across my gen set to try to remove the sender. I put a pair of channel locks on the square blue cap on the top of the sender. It does screw out. In order to do that. I went to disconnect the none waterproof spade connectors. When I did. They crumbled. They were severely corroded and the wires had a lot of corrosion wicking. I’m going to have to go back in and replace all the wire where the corrosion has gotten between the copper and the insulation (Wicking).
But for the time being. I cut out the connectors and some of the bad wire and reconnected them with waterproof heat shrink butt splices. Boom! My water gauge works perfect.
Ive attached pictures.

USMM - thanks for your knowledge & your reporting - life is getting easier - hope you continue to have the same problems I do - keep up the good work

 

[Aquanut2]

Having a similar problem on my 04 300 Marlin checked the gauge by shorting black to blue it read full looked at the sender and it completely fell apart any idea where to find a replacement? There is a number on the blue plastic cap WU-15 83 think the tank holds 32 gals in the GW parts manual I found 19-137 Sending Unit Water Tank 15” but not sure who the OEM is & where to buy one.

 

[Aquanut2]

Just so others searching for this sender can find it thought I would share the part source. It's made by KUA Model S3U Sender it has a 1.25″ BSP Mount - 15" × 1 Looks like it is all SS now with no plastic blue cap.

S3U Sender - 1.25" BSP Mount| Liquid Level Sender | KUS Americas, Inc.

Our electric liquid level senders, like this S3U, offer the greatest reliability and durability. That is why you'll see it in a wide variety of applications.

kus-usa.com

 

[Meanwhile]

Just so others searching for this sender can find it thought I would share the part source. It's made by KUA Model S3U Sender it has a 1.25″ BSP Mount - 15" × 1 Looks like it is all SS now with no plastic blue cap.

S3U Sender - 1.25" BSP Mount| Liquid Level Sender | KUS Americas, Inc.

Our electric liquid level senders, like this S3U, offer the greatest reliability and durability. That is why you'll see it in a wide variety of applications.

kus-usa.com

Thanks for the info. On my Marlin I have the same setup. How did you access the back of the display? Mine is located in the head on a solid wall. I need to dig in but thought you could save me time.

 

[Aquanut2]

Thanks for the info. On my Marlin I have the same setup. How did you access the back of the display? Mine is located in the head on a solid wall. I need to dig in but thought you could save me time.

Take the small angled starboard off where the panel wall meets the ceiling its pain to reach but u can unthread the large back nut that holds the gauge to the wall. I could not get to the connector but there was enough wire to pull it out from the wall.

 

[Meanwhile]

Take the small angled starboard off where the panel wall meets the ceiling its pain to reach but u can unthread the large back nut that holds the gauge to the wall. I could not get to the connector but there was enough wire to pull it out from the wall.

Thanks so much. Feedback like this is why this site is so valuable.

 

[Aquanut2]

Thanks for the info. On my Marlin I have the same setup. How did you access the back of the display? Mine is located in the head on a solid wall. I need to dig in but thought you could save me time.

Before you dig into the display side remove the connector at the sender and short the 2 pins if the gauge reads full then you'll know the display is fine and the sender needs to be replaced. BTW you have to turn on your water pressure switch to supply power to the tank indicator.

 

[Meanwhile]

Before you dig into the display side remove the connector at the sender and short the 2 pins if the gauge reads full then you'll know the display is fine and the sender needs to be replaced. BTW you have to turn on your water pressure switch to supply power to the tank indicator.

Thanks for that tip. I'll do thar.