1984 Mercruiser 120R outdrive self destructed.

[achris]

Re: 1984 Mercruiser 120R outdrive self destructed.

That's interesting. The tag says it is an R model but the serial number says it is an MR. I haven't seen anything that tells me what is the difference. I am looking at EBAY to see if I can just find one that is used.

The 'R' on the tag indicates it's a right hand drive. And the serial number comes back as a 1984, which is an 'R' model ('MR' started the next year)....

A couple of major differences.
Drive-shaft bearing in the lower unit is 'taper down' in the R, requiring a 'pre-load' pin at the top is the drive-shaft.
Gears in the lower housing cut differently between the R and MR.

Externally you can't tell the difference... It's all about what goes on inside...

Chris......

 

[sjoefl01]

Re: 1984 Mercruiser 120R outdrive self destructed.

Update: I've decided to go with the SEI drive but I will need a couple of paychecks first. While I am waiting I was going to install a bellows kit to be on the safe side. After studying up on that I decided that it looked like more work and possibly special tools than I wanted to put in. There was no sign of water encroachment and everything looked good. When I looked at the kits I got myself confused. There were 2 hoses and a lot of Orings that I had no idea where they go. On the surface whee the outdraive mates I only see one water inlet with an Oring and a hose on the back side. The gen II comes with one hose. Is there another hose that I am not seeing? Does anybody have suggestions about this installation? I guess I'll get on of the install kits and use whatever comes with it but for the most part it just looks like I need to line everything up and put the 6 bolts back on.

 

[Fishermark]

Re: 1984 Mercruiser 120R outdrive self destructed.

There are a lot of kits, so hard to say what you are looking at. Most of the "kits" will include all the bellows (there are three), the water hose and a gimbal bearing. They may also include the gasket and o rings to install the drive.

You may not need all the stuff in the typical kit. Evaluate what you need to replace and go from there. The driveshaft bellows, (the big one) and shift cable bellows are the ones you need to worry about. The exhaust bellows is no biggie as it will not allow any water leakage if it fails. No need to replace the gimbal bearing unless it is bad. The water hose itself - evaluate your old one and go from there.

 

[sjoefl01]

Re: 1984 Mercruiser 120R outdrive self destructed.

While I am waiting on my sterndrive I would like to change the engine oil. The boat is a 1984 Cheetah 166 with a Mrecruiser 120HP 4 cylinder. The last inboard outboard I had you had to pump the oil out. Is that the case with this one? Do we have any tricks? I don't have any instructions and haven't gotten a book on the boat yet. I don't even have a pump yet. Is there a particular pump? I'm sorry I ask so many questions. I come up with this stuff at night when I can't go out and look. I am going to do a little corrosion control tomorrow so the tilt unit is ready for the drive when it comes. I also plan to go fishing. It can't be all about work. Thanks everybody.

 

[SgtRollo61]

Re: 1984 Mercruiser 120R outdrive self destructed.

Hey!! I know this is a little off the topic... but... do you have any pictures of that boat?? I have an 84 Cheetah 176 with a 185hp 3.8 V6

 

[SgtRollo61]

Re: 1984 Mercruiser 120R outdrive self destructed.

You can get a cheep pump at Walmart that goes into the dip stick.. It's slow but it works.. After you get the oil out I would recommend getting a Oil drain kit from ********.. It makes it so much easier to change your oil..Take the oil pan drain plug out and replace it with the adapter then screw the hose into the adapter.. Then when you want to change your oil, reach into the bilge and push the hose out your drain plug on the transom,undo the cap and drain the oil....walk away for a little while.... come back when the oil pan is empty, put the cap back on the hose.. Push the hose back into the bilge, refill with fresh oil.. your done! ( don't forget new filter!)

 

[Don S]

Re: 1984 Mercruiser 120R outdrive self destructed.

You still have to pump the oil out of the engine, but you need to warm the engine up first, it makes the oil easier to change. Then just screw the pump to the hose thread at the top of the dipstick, the tube runs to the bottom of the pan.

Did you ever find the problem with the drive? No mention of what you found wrong causing the engine to not crank over, just suddenly you decided to get a new drive.

 

[sjoefl01]

Re: 1984 Mercruiser 120R outdrive self destructed.

Sorry Don. I thought I had reported back. I drained the oil in the foot. There was about 2 tablespoons of water and not nearly enough oil. When I took the cap off the top and looked inside the bearing was completely melted down and had wallowed out the cap. I'm fairly sure that the outdrive was run without much oil and a little water. That was my fault. The guy I bought it from admitted he knew nothing about boats. I was so excited about getting the new boat I wanted to take it out before checking all the fluids.
Like the seller, I am not an expert with boats and the guy up the street gets $100 an hour to work on them. I chose to order the new drive and install it myself as opposed to paying him to change the bearings. I like the warranty that comes with the drive and I was warned that the other bearings and gears were probably dry and maybe damaged also.
That brings to mind a question. There are probably a lot of good parts in this old unit. I don't have any where to store it so I will probably put it on Craigs List or Ebay. What do you guys think the unit is worth for parts? It would be nice to recover a little of the costs.

 

[Don S]

Re: 1984 Mercruiser 120R outdrive self destructed.

I guess I must have missed that post, I see it now. Sorry 'bout that.

You probably won't get much for parts, without all the special tools to reshim different parts, there isn't any reason to replace them. But what the heck, post them and see if someone buys them. People spend money for useless junk all the time.

 

[sjoefl01]

Re: 1984 Mercruiser 120R outdrive self destructed.

Hey!! I know this is a little off the topic... but... do you have any pictures of that boat?? I have an 84 Cheetah 176 with a 185hp 3.8 V6View attachment 178177

I am going to do some work to get ready for the drive today. I'll take a few pictures after I get it all shined up. The trick will be figuring out how to upload them.
It's a beautiful boat. It has been covered or in a garage all it's life (so I am told). The upholstery looks great as does the carpet. The dipstick looks like brand new oil. The 10 minutes I got to drive it were a blast. It was pretty choppy on the bay and the hull cut right through it for a smooth ride.

 

[sjoefl01]

Re: 1984 Mercruiser 120R outdrive self destructed.

I still haven't had a chance to take the pics yet but I came up with a quick question. When I was driving the boat it was pulling really hard to the left. The anode thing looks straight. What is the procedure for aligning the steering?

 

[Don S]

Re: 1984 Mercruiser 120R outdrive self destructed.

From the stickies at the top of this forum.

 

[sjoefl01]

Re: 1984 Mercruiser 120R outdrive self destructed.

I put the new stern drive on Friday and took the boat out today. Thanks to the folks that suggested SEI. It went on fairly easy. They could have had a little more information in the instructions and the $55 kit was missing some parts. I still had to tear into my old drive to get parts. Overall though I was happy. I put two hours on the break in today and it ran perfectly
I have two slight problems now. About 1 out of ten times when the shifter is in the center locked position the drive is still in gear. My buddy and I adjusted some cables on the top of the engine where the throttle cable met the shift cable. I thought we had it fixed but it did it a few times today. I have another problem where it goes dead when you shift into reverse unless you just romp down on it. This is driving me crazy. I don't see why the engine would care whether you were going forward or reverse but it does. This is a 120hp. I think it is made by Chevrolet (1984 Mercruiser). Any ideas?
Thanks again for all the help. I probably would have paid the boat mechanic a grand and I would still have a repaired drive with no warranty.

 

[Don S]

Re: 1984 Mercruiser 120R outdrive self destructed.

Are you adjusting your shift cable to specs or to what you think it should be. It could also be the lower shift cable is just worn out, and binding.
here is how to adjust it, and DO NOT skip any steps if you want it to work right.

View attachment A1 Shift Cable Adjust.pdf

If it won't adjust, replace it, and use the OEM replacement cable, not aftermarket. MUCH better quality cable.

 

[sjoefl01]

Re: 1984 Mercruiser 120R outdrive self destructed.

Thanks Don. I will give this a shot. I hope I don't have to replace the cable.