1991 Mercury tilt and trim

[tannedman]

Question i bought this last fall late was told the trim needed a bushing in it it worked going down but will not go up another suggested it was the silonoid for the tilt and trim i see that 1 of the connecters have no wires going to it anyone have any ideas or some diagram i could use that might help it is a 1991 3 cyl with oil injection Thanks

 

[Texasmark]

Re: 1991 Mercury tilt and trim

I have an '02 and my Merc Serv Man goes back to '97. Will assume yours is the same since you are above the '89 changeover from 6 cyl to 3.

My trim and the one that is in the book has a single piston to do both jobs and one motor/pump assy. The motor is controlled by the blue and green wires entering it. It requires 12v and gnd (+/- battery terminal power/return.....return is usually picked up off the engine block to which the battery - lead is usually connected).

My system uses 2 relays for that job which look just like the starter solenoid so you have 3 relays that look alike.....somewhere under the engine cover.

Your trim/tilt switch energizes one or the other depending upon whether you push the UP button or the DOWN button. Power to the motor is routed through both relays to get the required reversal of the +/- voltage at the blue-green wires.

So when going up, the up relay energizes and provides the 12v while the gnd is accomplished through the deenergized contacts of the down relay. To reverse the direction, the opposite relay energizes, reversing the voltage and the motor reverses. It takes both relays to do either job; only one is energized at a time but requires the other to complete the circuit.

The power to your relays (solenoids) comes from the trim switch via the blue/wh (up) or green/wh (down) wires to the respective relays. When energized (12v on either wire) you can hear a "click" in the relay when the contacts close (are supposed to be closed). The closed contacts send 12v out the blue or green (solid) wires as selected via the high current contacts on the relay. If the contacts are crudded up you will hear the click, but the voltage will not transfer from the red wire, to the pump motor, via the blue or greenl wires.

No click, probably wiring issue between control switch and relay. No voltage out, bad relay.

So, now you know how it works, just look for what isn't there that I mentioned.

Mark

 

[tannedman]

Re: 1991 Mercury tilt and trim

great ill keep looking for the other as i can only see 1 relay near the top right hand side of the moter

 

[Chris1956]

Re: 1991 Mercury tilt and trim

It is important to determine if the PTT motor has three wires or two. Three wire motors use a common (black) wire which is always grounded. To run the motor power is fed through either of two solenids to the green (down) or blue (up) wires to the motor.

Two wire motors do not have a common ground. To make the PTT pump turn, power is fed into one of the wires (blue or green), and the other wire must be grounded. This switching is performed by relays. The relays at rest ground the blue or green wire. When they are energized, they feed +12VDC to the blue or green wire.