1973 OMC 120 Binding

First post here, hopefully I can describe this well enough to maybe receive some help... I have a 73 OMC 120 with the electric shift. I believe this is refered to as the stringer outdrive.

So the first time this happened I was in a slight left turn at about 3500RPM and the engine just died with a clank from the back of the boat. Thought I seized my engine. I realized that when this happened it also turned my steering wheel all the way to the left. I tried to start the engine and immediately the steering wheel was turned. I figured that there was nothing that these items shared in common. when I turn the steering wheel it actually trys to turn the motor. I waited about 10 minutes and tried again and the engine started and idled just fine. put the boat in forward and the drive acted as it should. I tried to take it easy back to the dock and after about 100ft and 30seconds the engine stoped again and the steering again was binded to the engine. When the steering wheel is moved the engine again tries to turn.

Took it home put the garden hose to it and it ran for over an hour no problems... I dont know what to look at or where to start. What can bind up in the outdrive that would stop the engine and bind the steering to the engine. Any information would be great, or some guidance as to where to start.

I am mechanically capable, just looking for some knowledge from someone who has maybe seen this before?

Thanks in advance!

Re: 1973 OMC 120 Binding

gears and/or bearings have piled up in your outdrive.
Start draining the fluids and see which compartment runs out as a slurry of oil, steel and water...

Re: 1973 OMC 120 Binding

Drained the two lowers and no indication of anything wrong. I looked at the owners manual and it says that the upper has a fill/drain hole, but no direction as to how to drain and what level to fill to. I used a pump and pumped out what I could out of the upper and did not find any metal shavings, but the oil had a green/white tint and I also think there may be water in this case because it was definatly frothy...

Re: 1973 OMC 120 Binding

Yup the drive needs to come apart.

Re: 1973 OMC 120 Binding

can't follow.

from the engine to the prop power flows through:
Intermediate
Upper
Lower

Intermediate would not cause the drive hard-over steer described.
Suspect upper first. How's the ball gear wear? Are the ball gears worn on a 45 degree angle?

Hard to believe a bearing locked up 120HP worth of engine and no metal came off.... never seen that before.

Did it ever work right? or is this a new-to-you boat?

Kmoyer said:

What can bind up in the outdrive that would stop the engine and bind the steering to the engine.

Click to expand...

tight gear clearances, improper set up
tight tapered roller bearings - improper setup

Re: 1973 OMC 120 Binding

Do you have the True Course steering? I wonder if you do and the gears in the rear are binding. If you do not have any external steering mechanisim mounted to the top of the outdrive then you have the True Course steering. Look down on the port side in the rear and see if you have your steering cable going to a box. Its been a while since I worked on one but see what you can do with what info we have so far.

Re: 1973 OMC 120 Binding

doesn't matter which steering system he has, when the outdrive seizes up anywhere in the powerflow beyond the horizontal shaft in the upper, it steers hard over as the lower unit rotates around the seized component

Re: 1973 OMC 120 Binding

I guess I needed to read the post. My bad. I didn't read the engine stalling even though he said it more than once. I hate mondays.

Re: 1973 OMC 120 Binding

Thanks to all, I am out of town for the next 4 days, but when I return I am pulling apart the upper first from what I am gathering... I did look at the wierd looking ball gears and there is some wear but nothing that I would determine excessive? from what I can tell they are worn down about 1/8th inch from where they started.

I have had this boat running and it ran great last summer after purchasing. Took it out for the first time this year and no problems, but the second and third time this is what I get, Damn... Boat " Bring out another thousand"...

Thanks again to all who have replied, I will post this weekend when she gets pulled apart!!!

Re: 1973 OMC 120 Binding

Well where do I start. Pulled the upper and lower away from the boat. Separated the upper and then tore it down. No wear to even speak of on any of the gears internally. there was a little resistance in one of the bearings which holds the vertical shaft in the upper case. But this bearing was smooth and no grinding inside and no signs of wear.

going to pull apart the lower hopefully soon, just very busy with work, will post any findings after I pull it apart.

Thanks again to all who have given input!!

Cheers,

Re: 1973 OMC 120 Binding

Check the shift wires if they are chaffed and touching when you are turning you shift into both fwd and rev at the same time and kill the engine. good luck Bill

Re: 1973 OMC 120 Binding

Thank you, I am going to check them today, is there a specific ohm value I should get from each coil???

Thanks again.

Re: 1973 OMC 120 Binding

Yeah...

Well I have learned somthing the hard way... Not all Hi-Vis drive lube is created equal. I used just a standard Hi-Vis lube from the local dealer, and that is not what was needed for the electric drive... Make sure that the electric drives get type "C" Lube

What was happening I am guessing after following all the leads above is that I was energizing both the forward and reverse coils at the same time. Luckly I was able to dodge the bullet this time by not running the engine really hard and was able to not damage any of the internal parts of my drive. The Hi-Vis lube that I was using was not type "C" and it was allowing current to travel through the lube and energize both of the coils.

Well after many evenings of sitting down to tear down and rebuild my outdrive I now know how it all works and is put together, not really that bad, easier than I though it would be. And it also assured to me that the drive was not damaged in any way. and allowed me to replace the empeller for the cooling system while I was in there!!!

So thanks to all that provided information it is greatly appreciated. I now have a boat the runs like a champ!!! have put about 4 hours on it since just replacing the fluid with type "C"!!!!

Cheers,
Kalan