OMC Cobra Inspection hole, Port Side

[chopperdog]

Recently serviced 1988 OMC Cobra on a 3.0L 4 cylinder. The shop replaced a mildly bent shift rod.
They also sealed up the inspection hole on the Port Side of the Upper Unit, because they said it had a small leak out of it.

While boating, Engine started getting hot. We determined that there was no water coming into the engine from the outdrive (removing hoses to check flow).
We played it safe, and got towed back to the dock.
The "patched" inspection hole was now completely open. They screw was gone, everything. It was just a hole.

With this plug missing, could this have caused a lack of water pressure flowing into the engine?

Thank you,

Chopperdog

 

[HT32BSX115]

Re: OMC Cobra Inspection hole, Port Side

Howdy,


Yes, it would allow water from the raw pump to exit there. and very little if any, would make it to the engine.


It's not an "inspection" hole though..... The OMC service manual is pretty much silent on the purpose of the hole.

Some of us call it the "Do not remove" screw!

You should find some way to close it either using the original type screw/bolt, or some other permanent cover.

It'll probably require you to remove the drive so you can get in there and put a nut-plate behind to "screw" into. then put epoxy over the slot so someone else doesn't try to remove it!



Cheers,


Rick

 

[chopperdog]

Re: OMC Cobra Inspection hole, Port Side

Thank you for the response.

I have an extra gear housing. We may be able to get the screw from that drive.

It's nice to at least know the cause of the overheating, so we can cure the problem.

Thanks again,

Chopperdog

 

[HT32BSX115]

Re: OMC Cobra Inspection hole, Port Side

Well,


That may not be the "cause" but would certainly contribute since you're not getting full water "flow" from the pump.

If you have pump fragments from a previous impeller failure ALSO blocking flow, then you may still get overheats.....

You DO need to close that hole though!!

 

[starsnstripers]

Re: OMC Cobra Inspection hole, Port Side

My drive has a hole there too. 1988 Cobra, i have one of those rubber plugs in it. It's like the ones used on the transom drain hol with a lever you flip to tighten it, sorta like a rubber freeze plug that you can tighten. It's great because when you drain for winterization you can pull the plug and drain all the water out. I wouldn't close it off permenatly. Quite a bit of water stays in there after you shut the boat off. Mine is like a 1-11/4 hole i'd say. Unless you live where it doesn't freeze in the winter.