Mercruiser Trim Sender wires

[canuto]

I have a 1975 Mercruiser I/O Stern serial #4426063 and noticed extreme corrosion on the wiring plugs inside the engine compartment. The trim pump works fine when I'm lowering the motor, but when I try to raise it nothing happens. I suspect two of the wires are shorting as they get close to the power trim sender. I want to replace the wiring into the trim sender with new wiring but it disappears into the gimble and I cannot locate it on the other side at the stern drive. I'm limited to what I can do with the stern since I have to manually raise it by brut force.

I have a manual but for the life of me, I cannot locate it on the stern Can anyone tell me where the sensor is,
Thanks for any help. With this stern type can it be be on top or well hidden?
Pics and advise appreciated.

 

[Haut Medoc]

Re: Mercruiser Trim Sender wires

The only place those go is to a switch that shuts the trim pump off when it is 'full up' in the trailer position....
The "cut out'" switch....
That switch is located in the top of the transom shield above the bell housing....
When the bell housing closes that swich, it stops the trim pump....
I forget if the switch needs to be opened or closed to operate.....
I would try to bypass it to see if you get results, & clean the electrical connections at the pump itself......
The answer should be in Merc. manual # 2 chapter 7 if I recall......
Is this the manual that you are referring to?.......

 

[WillyBWright]

Re: Mercruiser Trim Sender wires

If you have the three-button dash assembly, if you push both upper and center buttons, it bypasses the trim limit switch. If that doesn't happen, you have a bad switch or a bad solenoid, or maybe a bad trim pump motor. Or a loose connection.

The sender is only for a gauge. It doesn't affect function.