OMC 4.3L I/O - what plugs the hole?

[asdasc]

Hi all,
I have a 1990 OMC 4.3L I/O. On the outside of the upper unit, there is a nice Cobra embem on either side.

When I pulled the boat out to winterize it, i found the port side emblem is missing, and there is a hole that leaks out all the red pop I am pouring into the PS cooler hose up by the thermostat.

I have a factory service manual, but can't find anything that mentions what that hole would be for, or what is supposed to cover it. Does anybody here know? I am kind of afraid to try pulling the starboard side one to look in there.

Thanks,

 

[Gary H NC]

Re: OMC 4.3L I/O - what plugs the hole?

That is supposed to have a threaded screw with a backing plate.
Someone must have made the mistake of taking that screw out in the past and just putting the cobra emblem back over the hole.

It is just a water passage but must be plugged.
That is the screw on a Cobra that should NEVER be removed.
My bet is the backing plate is still inside the drive somewhere..

You need to pull the drive to find it.

Don't feel bad but this exact topic comes up all the time here on the forums...

 

[asdasc]

Re: OMC 4.3L I/O - what plugs the hole?

Oh crap. I was in the boat, and had a buddy pulling the screws on the lower unit to drain it. There was a screw he 'said' came out of there, but I didn't beleive him as there was nothing for it to screw into.

The drive was up at the time, so it may have fallen way back in, I didn't see anything in there. Well, it looks like I get to learn something new...

Pull the whole drive off?

Once I pull it off, can I get in there to remount the backing plate?

 

[Howard Sterndrive]

Re: OMC 4.3L I/O - what plugs the hole?

Pull the whole drive off?

Once I pull it off, can I get in there to remount the backing plate?

yes, and no

you'll have to "fish" the plate to the hole.

 

[asdasc]

Re: OMC 4.3L I/O - what plugs the hole?

OK, I did fish out 4 peices and save them. When I compare it to the ones in this post:

picture of parts someone else removed

I have the 3 on the left, plus another part that is really thin either plastic or light tin that was about the same size as the backing plate on the right, only much thinner. It has a hole in it, but too big to thread into. Maybe it was agasket or something to keep the metal backing plate from corroding against the inside of the housing. I'll look again, maybe I can fish out another part.

 

[asdasc]

Re: OMC 4.3L I/O - what plugs the hole?

By the way, does anyone happen to know if that piece is ferrous? If so, I have a magnet that might help me fish it out.

If it is aluminum or some types of stainless, then the magnet won't help.

Thanks,

 

[Bluestream]

Re: OMC 4.3L I/O - what plugs the hole?

Its aluminium or stainless...

 

[HT32BSX115]

Re: OMC 4.3L I/O - what plugs the hole?

By the way, does anyone happen to know if that piece is ferrous? If so, I have a magnet that might help me fish it out.

If it is aluminum or some types of stainless, then the magnet won't help.

Thanks,

Yeah.....someone removed the "NEVER-REMOVE" plug!!


It probably is stainless. otherwise it would corrode quickly!



If you haven't removed the drive(s) in more than a year, you probably should anyway so you can check the U-joints, bellows, gimbal, AND the alignment.

It is not mentioned in any of the OMC service manuals..... I almost think they might have planned to use it as a flush port but never did.....I think that would work pretty good.

I thought about using it that way when I had mine by installing a fitting and a plug. But I fixed it different way (as indicated in my "sig")

In any case, as previously mentioned, you MUST pull the drive to fish out the nut-plate and put it back on.


Regards,


Rick

 

[Gary H NC]

Re: OMC 4.3L I/O - what plugs the hole?

The square piece in the right of the picture looks about right.
JB Weld that sucker and tighten the screw so it does not happen again.

I assume the drive is off so inspect the bellows,gimble bearing and grease the u-joints....

 

[a70eliminator]

Re: OMC 4.3L I/O - what plugs the hole?

The starbird side Cobra badge has nothing behind it, only port side has the plugged hole beneath, just an FYI.

 

[cr2k]

Re: OMC 4.3L I/O - what plugs the hole?

Once again:

Never remove ANY screw from a drive that is Phillips head, or is or was behind a badge or decal. ALL oil drain plugs are flat blade screws. Other screws hold some things that require disassembly to replace.