1990 Cobra Sterndrive Question

[jfigura]

Facing the sterndrive, on my right, are the gear case drain plugs. On the left, in manual, shows a cobra decal,(at the upper portion of the gear case) but on my unit, I apparently had some sort of drain plug.

A "friend" removed that plug thinking he was removing the upper drain plug for the gear case oil. Don't ask how he confused right from left (in New Hampshire, there are alot fo people here like that)... Anyway, he unscrewed the plug and fresh water drained from the hole (we had just got done idiling the motor for 10 minutes with ear muffs on).

When he realized his mistake, he went to reinstall the plug, but it has a lock nut behind it that was not secured. In essence, he could not re-thread the plug and after trying to bring the lock nut forward to the hole, the lick nut disappeared inside the case.

What I am trying to figure out is, what is this drain plug? Again, in my manual, the schematic only shows a diagram there.

I took the boat to local shop, and at first glance, the mechanic was a little stumped as well, saying the same thing I have said :Generally there is a cobra emblem there..."

So, of course I am a little nervous now and hoping someone more experienced here will have an answer to what this is, and how I can recover the nut. I am praying I dont have to remove the unit to do so.

This is a 1990 2.3L Cobra unit.

Regards,

-_Joe

 

[Don S]

Re: 1990 Cobra Sterndrive Question

Yes, that screw has confused a lot of people. The screw holds a plate to the inside of the drive. What that plate does, I have no idea. You need to remove the drive, retrieve the plate and screw it back in place. Use some red Loctite 271 when you reinstall it so it doesn't come out again.
That screw is in the water passage thru the drive, who knows maybe the case would erode thru there with all the water going past so OMC just screwed a plate there? := := (Just speculation) then put a decal over it so people weren't tempted to remove it.

 

[jfigura]

Re: 1990 Cobra Sterndrive Question

Does that water passge go to the engine, or is it on it's way back out?

We are going on vacation next Teusday, need the boat. Wondering if I can get away with temporarily plugging the hole. Until we get back and can have the drive removed.

--Joe

 

[marunr]

Re: 1990 Cobra Sterndrive Question

I'm pretty sure that is water intake in that cavity. Either way, I would not run the motor without retrieving that plate first. I've heard they can be a pain to put back on.

 

[jfigura]

Re: 1990 Cobra Sterndrive Question

I went back down to the shop after I posted this and chatted with the mechanic. He showed me a drive torn down and what had happened.

We're going to go ahead and remove the damn thing. Boy, what a stupid mistake.

 

[DHPMARINE]

Re: 1990 Cobra Sterndrive Question

Yep ! it is a stupid mistake but fixable.The real Cobra mistake is when someone fills a outdrive like an outboard.

Has to be filled a lot more,like to the fill line on the dip stick on top of the drive.About 30 or so more ounces.

Fixable also,but the gears and bearings are about $1200.00 plus the rest,and labor.

DHP

DHP

 

[MD-80]

Re: 1990 Cobra Sterndrive Question

Yeah I just did this. It is a pain in the ass to get it back in there and you definitely have to remove the drive to do it. I had to use a ridiculously long pair of needle nose pliers to get it back in. It's pretty tight in that passage way. I felt pretty dumb about it to so I know how you feel.

DHP could you elaborate a little more on your post what do you mean be 30 or so more onces?

 

[Lou C]

Re: 1990 Cobra Sterndrive Question

The regular Cobra drive takes about 64 oz of fluid for a fliuid change. You must follow the OMC procedure, can't do it the Merc way or it will be underfilled. Get a good manual and follow it.

 

[DHPMARINE]

Re: 1990 Cobra Sterndrive Question

About 4 times a year I hear of a local Cobra owner changing his outdrive oil,only to just fill it until it comes out the plug just above the anti - ventilation plate.(like an outboard).

Cobras have a dip stick at the top of the drive.This is the level the oil has to reach.

DHP

 

[88 Capri (2022 SOTY)]

Replacement plug fix is available at 9xmarine.com under OMC section

This post is 16 years old, they probably fixed it