1977 115hp Trim/Tilt?

[mercman65]

I recently purchased a 1977 115hp Mercury with power trim/tilt. The motor runs but trim/tilt was disconnected when i bought it. I attempted to reconnect the hoses and wires but when i did i got nothing. Does anyone have a wiring diagram or any suggestions to help? Any help is greatly appreciated

 

[RRitt]

Re: 1977 115hp Trim/Tilt?

just hot wire the darn thing until it works. then put in your formal and final wiring. Personally, I would just buy a used trim relay harness off ebay or one of the sierra adapto-harness things. The Bosch headlight relays didn't really hit the boating scene until well after 1977. No matter what you do based on 1977 wiring diagrams will be inferior to any modern setup with auto relays. And the relays are only $3 each from auto-parts store so there is no reason not to keep some spares.

 

[Chris1956]

Re: 1977 115hp Trim/Tilt?

There is a three wire plug on the PTT Pump/resevoir. +12VDC Power is in the vertical slot, and up is the blue wire. Green is the down wire. Black wire on motor is ground. It should have a clean connection to PTT bracket, and to battery. You should have a one solenoid unit (up has solenoid). Down is just heavy wire from switch to PTT unit.

Fill pump/resevoir with 5W-30 motor oil, unless it already has autotrans fluid, then top off with ATF.

You should find a wiring diaghram on the maxrules.com website.

 

[mercman65]

Re: 1977 115hp Trim/Tilt?

Thanks for the reply chris, but actually mine has two solenoids on it im not sure what the difference is any further help is greatly appreciated.

 

[RRitt]

Re: 1977 115hp Trim/Tilt?

does it work if you bypass relays and connect it directly to a battery? Don't worry about the wiring until you have the hydraulics working.

The wiring is very easy to do. But when neither hydraulics nor electrical is known good then you need to work on hydraulics first. Otherwise you could end up chasing your tail. When your hydraulics are a known good I'll post an easy to understand universal wiring diagram for you.

 

[mercman65]

Re: 1977 115hp Trim/Tilt?

How do i bypass all of the wiring to just jump the pump to see if it works? Thatnks

 

[RRitt]

Re: 1977 115hp Trim/Tilt?

Connect the wires coming out of your trim motor directly to a battery. The black wire is common ground. The blue wire is up. The green wire is down. Never connect green and blue at same time - even if it's just a loose wire to ground. You will be telling motor to spin in both directions at same time and it might burn out.

 

[FISHINJUNKIE]

Re: 1977 115hp Trim/Tilt?

Is trim/tilt external? Which solenoid is blue wire connected to and green wire ?

 

[westexasrepublic]

Re: 1977 115hp Trim/Tilt?

pics? post a pic and if I have the same external pump as you ill post up a pic of the wiring...

 

[Chris1956]

Re: 1977 115hp Trim/Tilt?

OK, Normally 1977 PTT units have one solenoid, however, it really doesn't change much. Wire it as RRitt suggested and see if the motor spins.

 

[nathanhooper]

Re: 1977 115hp Trim/Tilt?

not trying to but in, but what does the solenoid do? I have the same unit on my 1979. It has the three wire harness, plus a separate two wire cord that goes out to the port side of the motor. It is some kind of switch, is that the solenoid? What function does it serve? The only way I was able to operate it was to jump a wire from it to the positive side of battery.

 

[Chris1956]

Re: 1977 115hp Trim/Tilt?

Solenoids are remote switches. You connect a light duty wire to the primary winding of the solenoid, and give the wire 12VDC at 4Amps, and they connect the secondary poles of the solenoid, allowing 12VDC at 100Amps to flow. This allows you to save from buying heavy switches and cables.

The solenoids are always mounted near the motor they allow to operate. In your case, the solenoids are mounted on the PTT bracket. That other wire is likely the trim limit switch.

 

[mercman65]

Re: 1977 115hp Trim/Tilt?

Here are the pictures of my unit.

 

[mercman65]

Re: 1977 115hp Trim/Tilt?

I was able to jump all of the relays and solenoids and confirmed that the motor does in fact work. I just need to make sure all of the wiring and the switch is right. Is it possible that one of the solenoids is bad? Any help is greatly appreciated thanks.

 

[marvin the minnow]

Re: 1977 115hp Trim/Tilt?

I have a similar problem, my down switch works and is spittingh fluid out the hydro lines but i can get the up to do anything. I am suspectiond a bad solenoid. can this be replace with any solenoid from an auto parts store?