75 Mercury 1500 Trim/Tilt Questions

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Hello. I have a 1975 mercury 1500 mounted on a 1982 procrft 1700 bass boat via a DI Turbo Jack jack plate. The power trim tilt unit has only two cylinders (one port, one starboard). I recently bought this boat and haven't gotten all the kinks worked out yet. Last time on the water, the boat would not plane. It was bow high as soon as i hit the throttle. The trim buttons on the throttle handle would not work. I now have them working.If someone could answer the folllowing questions I greatly appreciate it.

1) With only two cylinders, is this system a "tilt only" system? Am I able to trim the boat onto plane?

2)It has a tilt switch at the bow, one on the dash, then the Up/down trim buttons on the throttle. They are all wired into the same wiring to dual trim pump solenoids. Whether using the dash switch or throttle switches, operation appears to be the same. I have the Seloc manual and the wiring is close to what it shows except someone has bypassed the trim limit switches and they are gone. Will the trim system operate this way or do i need to re-install the limit switches?

3) The bow switch is spliced into the dash switch under the dash, then those wires are spliced into the throttle switch wiring just before the solenoids. Will this work as designed or do i need to re-wire them separately? The remote control box has a "Trailering" button, but it is inoperable. Im assuming the dash switch is to replace it.

Thank you for any assistance you can offer! Im kind of new to boat motors but this baby is making me a veteran quick!I will also have questions about gauges ( since none of mine work!) and such in the future. THANKS!

 

[Moody Blue]

Re: 75 Mercury 1500 Trim/Tilt Questions

I'll have a go at your questions, even though I'm not familiar with your particular unit.

1) My guess, is that it should operate as both trim and tilt. See (2) next.

2) Sounds like all the switches are wired in parallel, which is how it should be. Any one switch should operate the system in the same manner. The trim and tilt functions are the same except, the tilt function bypasses the trim limit switch(s) allowing the motor to raise beyond the tilt range. If the limit switches are bypassed, the system will work just fine, BUT you have to be careful while underway that you don't raise the motor too high which could bring the waterpump out of the water.

3) Can't offer much here, but by your description, it sounds like the system is working as it should. As I mentioned, all switches should be wired in parallel. Take a close look at the wiring and "clean it up" as required.

Good luck.

 

[Chris1956]

Re: 75 Mercury 1500 Trim/Tilt Questions

That motor has PTT. The two cylinders and trim pump/resevoir in the boat was an early Merc design. The trim limit switch served to only allow you to trim the motor within the transom brackets, before opening and stopping the trim action. On most boats the motor will ventilate prior to the trim limit switch opening, so it is largely unnecessary. The trim up button should be wired to power and the blue wire. The trim down button should be wired to power and green wire. All other PTT switches should be wired the same way, in parrlel.