Can I pair up my motor with this outdrive?

[psikys]

I have a 74 Galaxy with a Mercruiser 120 2.5L. Currently I have, as per a phone call and email convo with MerCruiser, an OMC 120 Stringer outdrive on the back. Supposedly, it's been that way from the factory, but I have no idea. That confused the guy at MerCruiser, so whatever. Having that said, I've had a number of "when that goes throw the boat away" warnings. I'm prepped for that.

Having that said, I've found a few "working" MerCruiser 120 Outdrives on FB in my area and I'm wondering if they're a direct bolt up, or would I not be able to pair them up? They are cheap cheap cheap ($75 each). I figure, if they bolt up, maybe I could frankenstein them together and get a complete outdrive or something.

Anyway, I have zero way of testing these. Just curious if they'd be good for parts. $150 for both?

 

[psikys]

Mods, please move this post...I thought I Was in the sterndrive sub...too many open tabs. Sorry

 

[GA_Boater]

Direct bolt up - Sure. After you get all the Mercruiser hardware between the motor and the prop.

And after you close that cavernous hole in your transom!

 

[psikys]

So the keyhole would be a different size as well?

 

[Bondo]

Supposedly, it's been that way from the factory,

Ayuh,...... Welcome Aboard,..... That's a False quote, just plain ole Wrong,..... Untrue,..... Never happened,......

So the keyhole would be a different size as well?

Yes,.... Very, Very different,....

 

[GA_Boater]

Moved to non-repair.

The Stringer is called a Stringer because all the motor and outdrive weight rests on the boat's stringers.

A Mercruiser rests on the the front motor mount and transom plate. So the transom holds the back of the motor and the weight of the outdrive.

Trimming a Mercruiser moves the outdrive, trimming a Stringer moves the motor and outdrive while pivoting on the stringer mounting. That's why a Stringer has a very large rubber diaphragm in the transom - To allow the up and down trim movement.


So yes, a Stringer has no keyhole. A few members have successfully converted a String to Mercruiser with a fair amount of wood fiberglass work.

Thanks, Bondo. I meant to address the factory thing also. Merc and OMC never exchanged parts. A prior owner used a Mercruiser motor to replace a bad OMC based motor by moving all OMC parts onto an M/C block.

 

[GA_Boater]

OMC Stringer hole big enough to drive a Mack truck through;




Mercruiser keyhole;

 

[psikys]

You're definitely right about the keyhole. Here are some pics I just went and took. I don't know why, but it never occured to me how large that hole is until just now. I mean wow.

Having that said, so I have the blue, Merc 120 motor, unless OMC made a motor that looks identical. I've found diagrams and pics of the Merc 120 and it's identical to mine. Kinda make sense why the throttle handle all says OMC as well. So was this motor dropped in?

Also, linked are some much better pics of the outdrive. Pretty well confirmed it's the Stringer...you say it's the 400 Bondo?

 

[GA_Boater]

The M/C 120 is the same as an OMC 120 except for the dressing - Exhaust and a few other things. A long block is identical for both.

One is paint - M/C uses black and OMC used blue. Unless someone painted the motor, you may have an OMC motor.

Look above the starter for a serial number plate.

 

[psikys]

Gonna crawl in there tonight and get a pic. The motor is most definitely blue. So I guess I do NOT have a Merc 120, I have an OMC 120.

So just how effed am I folks? I'm not super worried, like I said, it was cheap, and my goal of learning is happening. It runs, the only 2 problems it has right now are tilt doesn't work ( I can hear it but it does nothing ) and the steering is stiff as hell. The motor SOUNDS great, no milky oil, no filings in the oil. So all in all I'm not super concerned there.

 

[southkogs]

On your engine - likely on or near the rear motor mount on the starboard side - you'll find a tag. On a '74 OMC 120 you will find a number like 99021FF 74 or similar. That will tell you particularly which OMC 120 you have. It's based on the Chevy II 153 inline 4.

Your drive is an electric shift Stringer that someone painted black (you can see the white areas that didn't get painted). It's old, antiquated and most likely no one is gonna' want to work on it. BUT you can keep them going reasonably easily. I like the drive personally, but ... well ... you get ribbed for owning one

Is your tilt motor running? Or are you just hearing the solenoid click? Those motors are a pain ... and a pain to get to ... but not terribly hard to fix. (Motor is behind the engine, down almost into the bilge on the port side of the boat attached to the intermediate housing.)

For the stiff steering try 1) greasing the swivel bearing (Zerk is behind a plastic cover - looks like a nut) on the front of the out drive. If that doesn't work, try removing the drive see if the helm turns easily. If it does, then you may have to mess with the steering gears. You've got tru-course steering, which I've never had but know to be a really nice steering setup when it's working properly.

"When it's working properly" is a phrase you use a lot with a Stringer

 

[psikys]

The tilt motor is working. It's literally like the gears aren't engaged. Any idears?

 

[Bt Doctur]

the motor is connected to the impulse coupling, ,from there it goes into the gearing and clutch

 

[Bt Doctur]

http://www.omc-boats.org/archive/att-3596/Guide_to_OMC_Stringer_Power_Tilt_System_B.pdf

 

[Bt Doctur]

https://www.bing.com/images/search?...9C56DFD152E30700538966C9AAC566DC6&FORM=IQFRBA

 

[psikys]

A huge thanks to Bt Doctur, thanks to you I was able to figure out the problem to my tilt issue. Previous owner who "rebuilt" the motor and sterndrive, was an idiot. He somehow put all new clutches into the worm gear clutch assembly, but lost one of the required spacers. So instead of ordering the proper parts...he just put a washer in in place of the pressure plate that he lost....because that makes damned sense.

To clarify, the proper, working clutch order, is 4 clutch discs, separated by a total of 5 pressure plates. This doofus put them in the order listed as you see here in my attached images.

New part (well, used, but in working condition) ordered and will be here before week is through. Now to find out what other redneck engineering he's done to this boat.

As a final follow up question, how should I be lubricating all of this? I have 75w110 Severe Gear from AMSOIL and AMSOIL Marine Grease. Your guidance is greatly appreciated.

 

[southkogs]

Some people have packed them with grease, and it seems to work. I never did that with mine, and just used SAE 30 gear lube (which is what the manual calls for). My clutch pack never really gave me any trouble.

 

[psikys]

So, if I want to just throw some 75w110 (what I have) all over all the parts and then pack some marine grease in it, what do I lubricate? The clutches? That seems counterintuitive?