Broken tab on OMC cobra

[DaveD6688]

I just bought this boat on ebay. Cobra Sterndrive on a 1989 4.3L motor. The guy said it was winterized but when I got it home and pulled a couple of pet cocks on the engine block, pure water drained out so I drained everything, took off hoses and poured rv antifreeze everywhere I could find. Drained sterndrive gear oils and refilled. (upper and lower, no water in oil thankfully) Next is where my problem began: I removed what looked like a drain plug from the side cover (opposite side from oil drain/fills) of the upper gear housing looking for more trapped water and sure enough water came out there too. When I went to put the plug back in, I noticed that the threaded block inside of the housing was loose and no longer lined up with the opening. It looks like it was part of the casting of the gear housing. I can line it back up with the hole and move it around so that I can see al sides and it basically looks like some kind of tab that broke off from the casting. Is this what it appears to be or something more? I thought I would try to line it up with the hole using some adhesive to hold it in place until I can thread the plug back into it but not sure if there's something more going on. Please help!! Dave

 

[Don S]

Re: Broken tab on OMC cobra

First off, if you pulled the drain plugs and water came out, that could be a problem if you are where it gets cold enough for water to freeze. If not, no problem. But if you are where water freezes, untill you run the engine and drive you won't know if something is broken or not.
That plug with a plate on the drive, well, it's not a drain. You are not supposed to take that screw out, and it's normally covered with a decal so you can't see it.

 

[DaveD6688]

Re: Broken tab on OMC cobra

Thanks Don. It's not one of the oil drain plugs. This plug is on th other side cover. It's pretty close to the water impeller housing, about a couple of inches below and toward the stern. There is an o-ring on the plug and as I said, it threads into a separate piece inside of the housing but not the actual side cover because that is very thin. The space where the water came from looks to be between the outside cover and the exterior of the gear housing. If it's not supposed to be there, could the water be coming from the fresh water impeller or housing, gaskets etc? should i get a water pump kit and replace all of the parts? also, back to my broken tab problem: If I can get the cap/plug threaded back into the threaded block, should I do that?

Thanks, Dave

 

[Boatin Bob]

Re: Broken tab on OMC cobra

You'll have to remove the drive from the boat, there is a very thin nut plate that has fallen down inside the water passage that the screw goes into. You should be able to fish it out and then carefully hold it in place while putting the screw back in.

 

[a70eliminator]

Re: Broken tab on OMC cobra

Consider yourself very lucky to be able to thread the plug back in without dropping the nut into the housing, that cavity behind there does fill water so not to worry just do as you planned and put that plug back.

 

[Coors]

Re: Broken tab on OMC cobra

The OMC mystery plate bites again. Do you still have it held in place? Glue it, screw it, and never touch it again.

 

[DaveD6688]

Re: Broken tab on OMC cobra

Thanks gents. Well. I've tried every way that I can think of to get the threaded plate to stay in place while i screw the plug back in but have had no luck. I can easily line it up with the hole along with what appeares to be a gasket, but i just can't seem to get it to stick together. In addition, now it looks like the seat for the plug is caving in away from the side of the housing. I found a thread from months past showing all of the parts needed.

Can I buy all of the components on line somewhere? Are there any alternatives to replacing all of this stuff with the same junky set-up?

also, I'm a little nervous about pulling the sterndrive away from the pivot plate. Everything I've read says that I will need an alignment tool to get the spline back into the coupling on the engine. Is this correct?
I don't have a hoist in my garage or anything to fasten it to above so I thought i would try making a dollie to support it while its off of the boat.

Your guideance is much appreciated!

 

[a70eliminator]

Re: Broken tab on OMC cobra

You will need an alignment tool to reinstall the drive by the book, not that you can't do it, I mean if the alignment is true and nothings moved?
There's really nothing to pulling the drive, 6 nuts off then grab the drive and wiggle back and forth as you pull, once it begins to seperate be ready to reach in and grab the driveshaft so it don't just flop down. I highly suggest you pull that drive tool or no tool.

You don't need a hoist or anything, just put a block of wood under the skeg and lean the whole thing on the transom until your catch your breath, then you can lift the drive and carry it away, I'm just a pip squeek and I carried mine into the house and down to the basement, took a few rests in between. Tied it to a dolly with a rope on my second escapade, it way better.

If your drive pulls off smooth and easy chances are the alignment is good, if your stringers are soft and engine has drooped or you've his some underwater object and jousted the unit there could be alignment issues.



I'm basing all this info on what I've done on my own stuff, so the more veteran mechanics will chime in.

 

[HT32BSX115]

Re: Broken tab on OMC cobra

Yes,

You removed the "Do Not ever Remove" plug!

I am far more concerned about your

Drained sterndrive gear oils and refilled. (upper and lower, no water in oil thankfully)

Precisely HOW did you do this? Specifically how did you refill the drive. Did you have a service manual and follow it? If you did not refill IAW the OMC instructions, you will have a very rude awakening when you run it.

regards,


Rick

 

[DaveD6688]

Re: Broken tab on OMC cobra

Sorry Rick,the draining and re-filling of the lower and upper gearboxes comment was totally unrelated to my problem with the plug that I shouldn't have removed. I think I used the proper method when filling the units: After draining, I refilled the lower unit first by pumping the oil through the bottom drain plug with the vent plug at the top of the lower unit removed until oil came out the vent hole. Then after replacing the bottom plug, I moved my pump up to the previous vent plug and filled the upper box with the dipstick removed from the upper box and watched it fill the upper to the line on the dipstick. It took about 64 oz total.

 

[HT32BSX115]

Re: Broken tab on OMC cobra

Howdy Dave,


OK...well, the Cobra has a "vent/dipstick" hole (top), A drain hole, (bottom) and a "Fill port" in the middle.

OMC suggests (actually requires ) filling the drive from this middle "Fill Port". not the bottom.

Now there are some that say it's "OK" to fill from the bottom until the fluid gets to the "Fill" port, THEN continue filling from the "Fill" port.

That may work (it probably DOES work) BUT that's not what the service manual says.

I suspect that the REAL problem comes from doing the whole process from the bottom. It traps a fairly big bubble in the drive that works it's way to the top when the oil warms up from running.......which of course uncovers the upper gears and bearings.

I have a drive sitting in the garage right now that was replaced by a Four Winns dealer who thought it was OK to fill from the bottom!


If you got 64oz in yours doing it that way you're probably "OK". Many-A-Cobra had the upper gears/bearings destroyed by filling them wrong.


Cheers,


Rick

 

[DaveD6688]

Re: Broken tab on OMC cobra

Thanks Rick. I tell you, this forum is great! I realy appreciate all of you guys' expertise. I just wish I had found this site before I took out that stupid "never remove" plug. I was kind of freaked out after picking up the boat in Iowa, returned to Indiana and found the pure water in the engine drain cocks. I went a little crazy removing plugs looking for water. The boat is now in my attached garage which stays about 50 deg all winter so I'm feeling a lot better about it now. Now I just need to deal with fixing the problem I created.

Dave