1986 18' Cobalt 5.7 OMC

[midsouthfire]

Re: 1986 18' Cobalt 5.7 OMC

Decided to bite the bullet and remove the drive and fix everything properly. The starboard side of the outdrive seems to be cracked where the silicon is. Don't know how bad the crack is till i get the outdrive off. Has anybody ever used JB Weld or anything like that to fix a situation like this? As far as I can tell, that's all that wrong. It wasn't leaking with the silicon so there can't be that much water pressure. Also, does anybody have or know of anybody that has an upper gearcase housing for sale just in case? Thanks

 

[Lou C]

Re: 1986 18' Cobalt 5.7 OMC

If it's the starboard side as you face the rear of the boat, that is not a water passage, that is where the shift cable and guide come out of the gimble housing, but are you talking about the actual upper unit itself or the gimble housing that the drive bolts to? Because the gimble housing has 3 drains in it, two on one side and one on the other, that can have water in em that can freeze if not drained when winterized. I have seen thse welded up if cracked. The water passage is on the port side as you face the rear of the drive.

 

[midsouthfire]

Re: 1986 18' Cobalt 5.7 OMC

The crack is on the starboard side as you face the rear of the drive. The hole that I'm gonna plug is on the port side. So you've seen this welded up with no problems?

 

[Don S]

Re: 1986 18' Cobalt 5.7 OMC

does anybody have or know of anybody that has an upper gearcase housing for sale just in case?

You can't just move all the parts from one case to another, the gears have to be shimmed to the case.
Can you post a picture of this crack?

 

[midsouthfire]

Re: 1986 18' Cobalt 5.7 OMC

Here's the update, I took it to a shop here in Memphis and had the outdrive checked out. They pressure tested the outdrive, said it was good. Fixed the plug on the port side of the outdrive and "repaired" the crack by grounding the edges and sealing. The crack was not in a water chamber so there is no pressure. Now there is water running down the anode on the back of the drive. Is this normal?? I'm also gonna ask the mech. at the shop, would like to have a 2nd, 3rd, 4th opinion. Thanks

 

[Lou C]

Re: 1986 18' Cobalt 5.7 OMC

If you can post a pic of what they did, that would help. The water that is running down, are you talking about the little square shaped one at the tail end of the drive, or the big one that is at the foward edge of the drive? Motor off or running? With the motor running, it's normal for water to exit under the pivot housing so you will see water where the big anode on the front of the drive. Take some pix and we will see.

 

[Coors]

Re: 1986 18' Cobalt 5.7 OMC

Need pics.

 

[midsouthfire]

Re: 1986 18' Cobalt 5.7 OMC

Its the big anode on the forward edge of the outdrive and the water runs down the anode when the engine is running. I was going to take pics but couldn't find camera will take pics tomorrow

 

[Don S]

Re: 1986 18' Cobalt 5.7 OMC

It's normal to have water coming out of that area. There are slots cut in the exhaust bellows to allow water out, and the idle reliefs are just in front of the exhaust bellows and cast in the gimbal housing. Water will run down on the anode plate on the front of the drive.

 

[Lou C]

Re: 1986 18' Cobalt 5.7 OMC

Normal like Don said. When I run mine on the hose just about all the water exits under the pivot housing that the drive bolts to.

 

[midsouthfire]

Re: 1986 18' Cobalt 5.7 OMC

Here's the update. Replaced two freeze plugs then ran the engine. Everything seemed to be fine. Change the oil and found milky oil (great right). Took a closer look at the block and found three cracks. So now my next step is a new rebuilt engine. I started another thread for advise on engine builders.

 

[dhacker]

Re: 1986 18' Cobalt 5.7 OMC

The holes on the side of the drive are normally plugged with emblems. I would not weld the drive, adhesive would also be fine. They can be replaced without removing the drive by the trick of holding the inside retainer bar with a wire as the screw is started.

There was a starboard side flush kit as an option. With my upper drive I removed the port emblem and retainer to make my own flush port. I use the flush port to run the engine or flush the drive and head exchanger after each use.

How to install a flush kit: Using a ? inch steel pipe as a tap carefully thread the aluminum-casing hole. Screw in gently a short (brass ?? male pipe-to-garden hose thread adapter) into the hole with 3M 5200 Marine Adhesive. Cap the hole with a brass hose cover. I have installed this on two OMC drives used successfully the last 5 years.

 

[Gary H NC]

Re: 1986 18' Cobalt 5.7 OMC

This thread is over 6 months old......hopefully he has it fixed by now..