Mercruiser Trim Sender Issues

[tahoejag]

Problem: Trim Gauge Flucuating: At times the trim gauge will read accurately from all the way down trim to full up trim (on the gauge this would be like a fuel gauge reading empty to 3/4 full) The gauge has never read all the way up (or full, if you will). This excludes being or going to the trailer position.

​Is it possible to get the gauge to read or to use the full spectrum of the gauge. Could it be off one notch at the drive?

​Other times while underway the gauge will "jump, read or change" to full down trim (gauge will be at 1/4) and at full trim up (gauge will be just under 3/4). This fluctuation will happen while cruising or just erractically.

​I have checked and cleaned ALL connections that relate to the sender. I ordered and replaced the disk (potentiometer disk ??) inside the sender unit itself.

​Is there anything that I may be overlooking or need to recheck??? I thought I done my homework, but apparently not! :grumpy:​ I would really like a accurate reading gauge for the better half is learning boating and trying to explain to her "just listen to the drive and watch your rpms are a night mare!"

​Any and all suggestions are welcome! Thanks!

 

[JoLin]

My senders never used the full range of the dial on the gauge. In the end I just set them both up to hit the same marks on the gauges at the up and down limits of drive travel. I replaced them both last summer and one was a little erratic at times. It recently stopped working altogether. Haven't had that issue with the other. Go back and check your electrical connections.

 

[tpenfield]

Usually you replace the entire sender, rather than just the potentiometer wheel, as there could be internally frayed wiring. That could account for the gauge jumping around.

 

[scoflaw]

That potentiometer needs to be set to 16 to 20 ohms in the full down position. usually the wires are the problem

 

[tahoejag]

Went over all connections again and ran boat today. The trim gauge setting did NOT flucuate at all. Regardless of where I trimmed the motor, the gauge read appropriately to the setting. One quick note...the gauge reads off a bit but a slight adjustment to the sender will bring reading true to the gauge. Thanks all for the advice!