Trim Sending unit

[MYERST]

2 questions for a 1996 Mercury 175 EFI

i recently lost my trim gauge. I found the sending unit but how do I know it is bad? where can I get a new sending unit?

How do you know how much trim fluid is enough?

Thanks for any help

 

[hkeiner]

Re: Trim Sending unit

I found the sending unit but how do I know it is bad?

You can test the sending unit with an ohmeter. Check out the below linked website. It contains a troubleshooting guide titled 'Trim Gauges'

Good luck

http://ww2.tflx.com/tech.html

 

[Chris1956]

Re: Trim Sending unit

To fill the PTT Unit, Trim the motor all the way up. Remove the fill plug and squirt in some Dexton III ATF until it runs out the fill hole.

 

[MYERST]

Re: Trim Sending unit

Thanks for the replies, I cant wait to get home and test my trim gauge with a short piece of wire. Do you know if the sending unit wire goes directly to the gage or is there a relay inside the cowling?

As for the Trim fluid reservoir, the reason I asked was my "owners manual" stated to lift the motor all the way up and engage the arm. once done I opened the plug to the reservoir and fliud poured out as if it was completely full. I was thinking I did wrong but now it is at the level the book and
chris1956 say it should be at.

 

[hkeiner]

Re: Trim Sending unit

Do you know if the sending unit wire goes directly to the gage or is there a relay inside the cowling?

The wire should go directly from the sender to the gauge, as shown on the wiring diagram of Teleflex's trim gauge troubleshooting and installation links (see link on my previous post).

 

[j_martin]

Re: Trim Sending unit

The sending unit grounds through a mounting screw and then through a labyrinth of engine grounding jumpers. Mine was inop or flakey until I routed a ground wire directly to engine ground. Then all was good.

It's a variable resistor, and the wire routes up into the cowl, and then plugs into a pigtail on the harness. You should be able to read a varying resistance between that connector and ground. The wire routing is in harms way, and often gets injured.

hope it helps
John