Trim Limit and Sender Help

MS03

Cadet
Joined
Feb 12, 2024
Messages
6
Mercruiser 120 with Alpha One Gen One. Bought the boat a few months ago and I finally got it running but previous owner cut the wires to both sensors. I have new sensors but there is only about 1 inch of wire coming in from the transom and I have no idea where they would hook up to. Wiring diagrams have not been able to help because it seems all wiring has been ripped out.
 

matt167

Captain
Joined
Sep 27, 2012
Messages
3,952
I think the trim limit sender can be hooked up either way. Wires on my 1986 alpha gen 1 3.0l were both grey. Trim position sender may be polarity sensitive
 

Scott06

Vice Admiral
Joined
Apr 20, 2014
Messages
5,990
Mercruiser 120 with Alpha One Gen One. Bought the boat a few months ago and I finally got it running but previous owner cut the wires to both sensors. I have new sensors but there is only about 1 inch of wire coming in from the transom and I have no idea where they would hook up to. Wiring diagrams have not been able to help because it seems all wiring has been ripped out.
the limit switch plugs into the trim pump harness at the pump. The trim sender plugs into the engine harness and gets to the gauge that way.

You can jumper the limit at the pump to get it going, just be careful not to over trim while underway.

Not the best diagram sure you may be able to google another but may get you started https://www.perfprotech.com/blog/articles/mercruiser-trim-wiring

this link when expanded has a little better detail

 

tank1949

Lieutenant Commander
Joined
Apr 4, 2013
Messages
1,798
If ripped out, I suspect you will have to remove OD and install new sender/switches. That will cause you to curse a LOT. A nightmare to access...
 

1960 Starflite

Petty Officer 1st Class
Joined
Jun 23, 2011
Messages
365
If ripped out, I suspect you will have to remove OD and install new sender/switches. That will cause you to curse a LOT. A nightmare to access...
True, I spliced/soldered new wire on trim and stop limits, then ran them up an over transom until I needed to remove complete outdrive for repairs.
 

tank1949

Lieutenant Commander
Joined
Apr 4, 2013
Messages
1,798
True, I spliced/soldered new wire on trim and stop limits, then ran them up an over transom until I needed to remove complete outdrive for repairs.
I've seen boaters drill holes just above transom assemby to push wires in and connect to wiring harness. Use 5200 to seal wires going through transom. It may look like crap to others, but it works and easy to replace wires/senders, if needed later on
 
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