linear trim sender

[gadgeteer]

I have an older mercruiser (233 HP ford, alpha drive, circa 1977)<br />The power trim won't raise the outdrive. It will lower the drive but nothing happens when you try to raise it.<br />This installation has a linear trim sender (took me about 2 hours of searching just to find out what it is called and what it looks like.) does anyone have any knowledge of this type of sender and is there a trim limit switch somewhere? There are no "pucks" on the gimbal housing like the ones an my alpha 1 drive (another boat) and if there is a limit switch, I assume it must be somewhere inside the boat. Is there a chance the limit switch is part of the linear trim sender? Also, does anyone know of where I can locate a wiring diagram? I have a Clymer shop manual and the only reference it makes to the linear trim sender is how to test it.<br />TIA<br />Jim

 

[harveje]

Re: linear trim sender

There might a sender / switch inside the bellhousing, I think some pre-alphas had a different setup than the muff style senders.

 

[gadgeteer]

Re: linear trim sender

I replaced the bellows a couple of years ago and had the whole bell housing off. There is no limit switch (or wires for a limit switch) connected to the bell housing. As a matter of fact, there are no wires to the transom plate. Is it possible there is no limit switch? Also, this may not be wired correctly as one had to push both the "up" and "trailer" buttons just to raise the outdrive. (3 button trim switch). My understanding is the top button on the switch plate is supposed to raise the outdrive part way (to the limit switch?) and you press both the top and center button to raise it all the way. This is why I need a wiring diagram - to see if it is wired correctly.

 

[bigbrownbuku]

Re: linear trim sender

could be your switch is toast.

 

[gadgeteer]

Re: linear trim sender

Thanks for responding.<br />That was one of my first thoughts - I previously tested the switch with an ohm meter - it does work. This setup has a single solenoid. The Clymer manual refers to the "up" circuit and "down" circuit. I am assuming the pump is a positive displacement pump and runs in either direction to raise/lower the outdrive. If this is how it is supposed to work, does the solenoid somehow reverse the polarity, or does the switch do it or am I completely off base and in need of professional help. <br />Jim

 

[bigbrownbuku]

Re: linear trim sender

how many wires to the pump? if its 3, red/green/black ground the black then run power to either the red green for pump direction.<br />its its 2, red/green, ground the red and run power to the green then vise versa for the opposite.<br />narrow down your problem to switch, pump or wiring.<br /><br />test the pump as above. test power to the pump while pressing the switch to determine a wiring fault. test the ground side as well.<br /><br />the 3 button switches were rewired frequently with the removal of the limit switch at the drive.

 

[gadgeteer]

Re: linear trim sender

Thanks for the suggestions and info. The pump has three wires; black, green, and blue - the pump works, I then found the problem. There is a three prong connector and one of the prongs was bent and did not make a connection when plugged in. I found this after removing the pump (again), testing it as you described, and cleaning and re-tightening all connections. I had planned on testing the wires that run from the switch to the connector with an ohm meter when I noticed the bent prong. I do believe the original problem was a loose and/or corroded connection and created the new problem when I re-installed the pump.<br />Thanks again,<br />Jim