1975 omc outdrive

[fishkeeper59]

hello, i am need of some help as i just inherited a 1975 thunderbird 19c with a 165hp inline 6, the last time the boat was registered was in 92, so i take it that was the last time it was used, i have hundreds of questions im sure inthe future, but as of right now i am just trying to lower the outdrive and had no success, i installed batteries and tried to see if any of the electrical on the dash work, but i get nothing so bar other the bilge pump, to make a long story short is there a way i can lower the drive manually, it looks like it has lube box and gears sitting on the other side of box, i just want to replace oil and service the impeller, i would aqppreciate any help. thank you

 

[Howard Sterndrive]

Re: 1975 omc outdrive

remove the 3 bolts that hold the qaudrant gear to the drive. easiest way to lower it.

To replace the impeller, you want to take the drive right off the boat anyways, so kind of moot.

A factory manual would be the best investment for that beast.

 

[fishkeeper59]

Re: 1975 omc outdrive

Hello howardsterndrive, thank you, i agree that i need a manual, where can i get such item, and oh where should i start troubleshooting why my switch isn't working for lower unit? Thanks again for your response

 

[Howard Sterndrive]

Re: 1975 omc outdrive

ebay for a manual

start anyplace- the switch, the relays, fuse....

 

[fishkeeper59]

Re: 1975 omc outdrive

ok started troubleshooting tilt and trim problem,i feel i am over my head here, as i realize that tilt and trim has 2 different motors(kinda weird),i manage to locate what i think are the solanoids, 2 sets ,1 each set for trim and the other on tilt, i was able to get voltage in between the jumpers per solonoids(12 volts) but was not getting any to the connector(1.9 volt)going to motor of stern drive, how is the electrical voltage flow between battery,switch, fuse and solonoids? as you can tell i do not own a manual yet. any assistance would be greatly appreciated...

 

[Howard Sterndrive]

Re: 1975 omc outdrive

sounds like you're doing pretty good, actually
relay (solenoid) is a device to move high current to a motor, triggered by low current through the switch on the dash
http://www.explainthatstuff.com/howrelayswork.html

schematic- not your year exact, but most of your wiring will be same as this:
http://hhscott.com/evinrude/images/wiring/73_OMC_V8_all_big.jpg

 

[float2]

Re: 1975 omc outdrive

I had trouble with my 800 drive couldn't get it to lift. Pulled my hair out studying the manuals, tracing wiring, replacing solenoids, etc. Ultimately I a found plug under the dash that I simply pulled apart, checked for corrosion, then re-connected. At the time I actually had no idea that this plug had anything to do with the tilt. My drive immediately started working again! This plug was NOT mentioned anywhere in the manuals and reference material I studied.

 

[fishkeeper59]

Re: 1975 omc outdrive

Thank you both for your input,it starting to make sense now,as spent more time troubleshooting today and according to a schematic that i was following that the ignition switch was at fault since i am not getting 12vdc at the purple wire at the toggle switch, also none to the other two wires, it's a little complicated but i am starting understand the schematic, does the scenario sound correct? I am i'n the process of searching for the oem switch.

 

[fishkeeper59]

Re: 1975 omc outdrive

Ok quick update, after further investigation, found the main wire going into the tilt toglle switch cut(purple color), which is the reason i am not getting low voltage to the solonoid, leads me to a conclusion that at some point the tilt connection was bypass somehow, now my question, i need to know for sure if the tilt motor is non functional. between the 2 solonoids i get 12 volts can i jump the lead to the other bolt on solonoid to see if tilt motor activates?

 

[metalwizard]

Re: 1975 omc outdrive

I would suggest un plugging the motor and trying it without the solenoids at all
there should be a plug with two or 3 wires. one green one blue, possibly one black.

The black would be negative. if there is no black then it is grounded through the motor (common ground) apply 12 v to either the blue or green one is up one is down.

You asked about 2 motors or tilts. actually one is tilt one is trim.

the tilt should basically be to lift the drive up for transport. (mostly) it should either be used all the way down. when the motor is running. up to tow.

The trim should tilt the entire motor. same set up blur green and possibly a black. that can be run in any position. but use it to trim the boat and to get on plane.

OMC's are pretty simple for the most part. they are old school and hard to find parts for but they do work. so don't get to frustrated when it takes some effort to get everything you need to get them to work right.

I have a few extra solenoids if that happens to be your problem. But from my limited experience the motors tend to go bad first. I took mine to a motor rebuilder, and got them rebuilt for WAY less thanthe cost of a new or even used motor.

Good luck Oh I bought a manual from someone on this forum. I read through it a few times... learned a TON. well worth spending the $50 ish to get one.

 

[fishkeeper59]

Re: 1975 omc outdrive

thanks for the info metalwizard, i never understood why they lifted the motor, and i didnt know that the outdrive was meant to be euther all the way up or all the way down, that is so different from the the other outboard motors i've had, is it totally necessary to tilt the motor? as i can tell that they totally disabled that motor from working, i am still concentrating on the outdrive trim or is it tilt?,ao i need to create a jumper to put voltage in to the 2 wire connector before the motor, will try that in the am if its not raining. thanks again and if you have any other suggestion in regards to this motor i would definitely appreciate it, cant afford a manual yet, as i just dumped a $100.00 on a fuel line going into the gas tank(what a pain to put in).

 

[KRH1326]

Re: 1975 omc outdrive

Not as good as the factory manual, but here are some aftermarket ones.

These are the files that I supplied for the Adults only sticky. The links are gone now but the files are still there.

1964-1986 OMC sterndrive manual:

http://www.4shared.com/file/zF-DZrvB/1964_-_1986_OMC_Sterndrive_Man.html

1987-1998 OMC sterndrive manuals:

http://www.4shared.com/file/2Vy3uORd/1986_-_1998_OMC_Sterndrive_Man.html

1964-1998 OMC wiring diagrams:

http://www.4shared.com/file/K3ct2McS/1964_-_1998_OMC_Wiring_Diagram.html


Good Luck


EDIT -PS, if the motor is shot, chances are it is from water getting in thru the tilt box, then seeping up the shaft into the motor. Search these forums or my posts for topics about using grease in the housing, as opposed to oil.

Also, if the solonoids go, tho not likely, old style western snow plow replacement solonoids work AOK, and are duty rated for it.

 

[metalwizard]

Re: 1975 omc outdrive

Remember Trim is the angle of the motor (and the drive attached to it) that is what gets you onto plane..

Tilt. is the outdrive ONLY and you use that to transport the boat (so it does not drag on the ground)

When I first got mine the tilt did not work. BUT I could lift it by hand. so the first time I took it out. (to check out what other problems I had) I just used a tie down strrap to hold it up till it was in the water, then I let it down by hand. (let the tie down loose.)

So yes you can BUT I would not recommend it for anything more than a seaworthy test.

Justa note you can also use the tilt to get yourself out of a bad situation such as stuck in the weeds etc. BUT don't run it with it UP for very long it is REALLY tough on the ball gears.

I hope thats helping it all make more sense.

 

[float2]

Re: 1975 omc outdrive

While troubleshooting mine I was able to raise and then lower the drive by making a connection between both terminals on each solenoid. I just used a wrench outta my toolbox for this. Mine is a '78 so it should be pretty similar to yours. I have 3 solenoids on the back of the engine (305 Chev), one for raising, one for lowering, and the other is a start "assist" solenoid I guess. As long as we are talking solenoids I also have two on the front of the engine, one for trimming up and one for trimming down.

In my case I needed to replace a few solenoids which I got for roughly $20 a piece at a local parts store. Its kind of weird that although my engine is a Chevrolet they used Ford solenoids on this.

I feel your pain trying to figure out the tilt/trim system. I studied the OMC manuals which I didn't find that helpful for my particular set-up. I spent alot of time tracing wires, tinkering this, that, scratching my head before I figured it out. I really got to the point where I was going to sell my boat as is I got so frustrated. But its alot cheaper to tough it out yourself than pay a $100/hr marine shop that doesn't know how to work on these old OMC's anyways

Also make sure you have a good fully charged battery.

 

[Lakeshadow]

I found this searching. 1975 Slickcraft 302 Ford. My tilt is stuck up. At the little floating switch on the helm I get an amp draw yet motor does not work. I am trying to find out if something is stuck? Ordered 1975 OMC stern drive service manual, waiting for it.

I see this thread is from 2010, should I start a new thread for 1975 Slickcraft OMC stern drive tilt inop?

Thanks...

 

[southkogs]

I see this thread is from 2010, should I start a new thread for 1975 Slickcraft OMC stern drive tilt inop?

Yes please. Closed.