Logo
FULL SITE MENU

I need help with a screw on an OMC engine Have pictures

D

drewhiggs

New member
"Let me start off by saying th

"Let me start off by saying that I am not the mechanic in the family, but the one that wants to search online for an answer.

I took some pictures, which you can view by clicking the links below, of the problem in question and a few random pictures. You may notice that the prop and the carburetor are missing, but the prop is being rebuilt and the carburetor is being cleaned.

We just recently bought this 1990 Kayot knowing that it had been 2-3 years since it has been in the lake, but worked before that time. To test the engine, we put some ears around the engine before turning the engine over. When we turned the water on, a screw popped out of the engine. There are threads on the screw, but not in the opening that it popped out of.

We do not know if it is necessary to have a screw in this opening or if their was a nut that fell down when screw popped out. I would hope that OMC would not design a motor so that any num-nuts, like us, could unscrew something, only to have the nut fall into the engine.

The only fluid coming from the opening is water. From the first link, you can also see that there is some corrosion around this opening. Is it some sort of pee hole?

If you need anymore pictures, let me know. Thanks for any help that you can give me.


http://img375.imageshack.us/img375/9217/19352830zr0.jpg"
http://img75.imageshack.us/img75/4447/img0280oh4.jpg"
http://img375.imageshack.us/img375/8620/img0281dt9.jpg"
http://img75.imageshack.us/img75/4357/img0282yv5.jpg"
http://img75.imageshack.us/img75/7417/img0284ax4.jpg""
 
hundreds of people have actual

hundreds of people have actually taken that screw out by accident. No one really knows why it's there. it normally has a Cobra emblem over it so you don't see it. They refer to this as an OMC owner's "second mistake". Yours popping out might indicate the nut corroded off. I believe you have to remove the outdrive to install the plug
 
"Well that screw is not normal

"Well that screw is not normally meant to come out, in fact you don't normally see it. It's a water passage that was used during the manufacturing process. If you look at your 3rd picture
http://img375.imageshack.us/img375/8620/img0281dt9.jpg"

you will see on the stbd side of the drive in the same place there is a Cobra symbol badge, that screw is under this badge. Lots of guys have made the mistake of removing that screw because those badges fall off over the years. I suspect someone has done that in this case previously and probably tried to just stick it back in. There is a thin nut plate on the inside and you need to remove the drive to fish it out and reinstall it although in your case who knows when it came off and where it is. See the diagram below item # 14 is the screw and 12 is the nut plate. You might be lucky and the plate is still inside?


215309.gif
"
 
"Awesome, thanks for the quick

"Awesome, thanks for the quick replies! I'll post back with the results. It will probably be few days, but we'll see if we can find the nut.

BTW....what is the OMC owner's "first mistake?"

If we can not find the nut, will any plug do?"
 
"Chuck....just ask any Merc ow

"Chuck....just ask any Merc owner and he'll tell you that your "First Mistake" was buying an OMC !!!
rofl.gif
"
 
"Well does anyone have any hin

"Well does anyone have any hints on how to remove the lower unit? This thing will not budge. Better yet, does anyone have a manual?"
 
"Are you trying to remove the

"Are you trying to remove the lower from the upper while the drive is still attached to the boat? If so STOP. You need to remove the entire drive before you split the 2. If you are trying to find the nut plate it's not necessary to split the drive just remove the entire unit.

ps...for a manual you'll need to buy one, OMC factory ones are the best and can usually be found on ebay otherwise an aftermarket like Seloc or Clymers will work for some things."
 
"This message thread is extrem

"This message thread is extremely helpful, thanks! I just pulled the same stunt tonight by unscrewing what I thought was the oil fill plug, and the plate on the inside fell away. Yikes! I'd like to avoid major disassembly. Is it necessary to get the plate out to avoid damaging things, or is it in an area where it will do no harm? If it can stay in, can I just plug the hole with something fairly strong e.g. a plumbing-style rubber expansion plug?"
 
"Paul:
That plate is now loos

"Paul:
That plate is now loose in the water jacket and may, if unlucky block the cooling water from pump to engine.
Bite the dust, just pull the drive and get it back."
 
"Wow - thanks Morten for the a

"Wow - thanks Morten for the amazingly quick help! Will take your advice, haven't ever pulled the drive myself but grew up on a farm and know righty-tighty from lefty-loosey
Also have the manual, and best of all a friend who used to be a boat mechanic who just said the other day he took his stern drive off and put it back on in about an hour - maybe he can help. Keep up the great website! ps - this little plug screw is going in my collection of 'boat nails' someday."
 
"lol....that darn screw! Afte

"lol....that darn screw! After we fixed ours, we put some black silicon on the screw, hopefully to never make the same mistake again.

I have learned alot, after taking the lower unit off several times. First off, make sure your boat is far enough down on the trailer to have full range of motion with the lower unit. Our boat was to far up on the trailer, and it was a pain to line the shaft back up to put the lower unit back together.

Also, watch out for a black lever that the throttle cable attaches to (you will see it once you take the lower unit off). When were trying to shove the shaft back in, we bent this lever upwards, which would not let the boat go into reverse when the lower unit is put back together. After several disassemblies, we found that it was this lever, and pushed it back down.

Overall, it was a good learning experience. let me know if you have any other questions."
 
WOW the same thing happend to

WOW the same thing happend to me this past weekend. I thought that was the most rediculous thing I ever saw I managed to get the nut plate out and I simply looked around for some way to plug it. Guess what fit perfect? A bilge plug (compressed rubber plug). Screwed it right in and Bam. No problem. I wonder what would happen if the thing leaked. Any risks?????
 
"Yes, big risk. If your plug

"Yes, big risk. If your plug comes out the water being pumped up to the engine from the raw water pump will take the path of least resistance-out the hole and back into the lake. Hot engine in a hurry!"
 
"Darn, Thats not what I wanter

"Darn, Thats not what I wanter to hear. Any other solution besides removal of the drive to put back a lousy part.. Remember my case is a bit different that the others in chain. I have the nut plate removed and simply need to plug the hole, permently!
That darn screw is really short. There is no way to hold the nut plate and start the threads. Its a horrible design."
 
How did you get the plate out?

How did you get the plate out? One guy on here said he was able to reach something in through the raw water pump housing and hold the plate in place while he put the screw back in???? Most folks pull the drive off. Never had the problem myself so I'm not sure what is possible.
 
"How in the world did you remo

"How in the world did you remove the plate without taking the drive off? The plate that fell out for me, was a rectangular nut that would never fit through the hole.

I agree that it is a horrible design though."
 
That would be promising. I wo

That would be promising. I wonder if there really is a view to that hole from the raw pump .
See I was not removing the screw I saw water leaking and gave it a turn and the threads and plastic bushing that covers the hole gave way and fell out. I stuck a needle nose in there and wiggled the nut plate out. The reality is I probably need new parts. Thats probably not going to happen huh. Where would I get that. I guess I could fab something up. I run in salt water so my material options are limited. Otherwise I would have dropped in a butterfly nut like drywall anchors and been done.
 
"Do you see the parts you took

"Do you see the parts you took out in this picture? Usually #14 is the only one removed, then #13 falls off inside.

217743.gif
"
 
14- removed
11-cracked a bit

14- removed
11-cracked a bit but I managed to epoxy it back together.
58-is removed.
9- removed.
12- removed
The reason I thinbk I was able to get the nut plate our is b/c #11 bushing came out and the hole is much bigger now. Its almost 1" without it. Do you have aprt numbers for all these
So you think I might be about to get something to hold it from the raw pump side. Interesting. I hate taking the drive off
 
It is less work pulling the dr

It is less work pulling the drive.
6 nuts and the bolt through the trim-cylinders.
Another thing: By pulling the drive You get access to the grease zerks on the u-joints. When was that last lubricated?
When did You last check the joint bellow and the gimball bearing?
Is Your support-plates (#61) still in place?
The reason for the hole in first place has to do with casting/machining of the upper unit.
The main reason for this screw to be removed in the first place is normally that people in general never reads the manual until everything stops working! Even the owners manual that follows the engines describes how to change oil. I do not think it is quite fair to 'blame' the screw.
 
"The starboard side plug is sh

"The starboard side plug is shown in the above diagram, but my problem is with the plug on the port side. I'm assuming after pulling the drive, there will be an opening to reach in with a needlenose pliers to retrieve port side plate #13 and hold it to remount port side screw plug #14, right? If not, what's the recommended access path/technique for plate retrieval and holding for the port side?"
 
"Starboard side goes into the

"Starboard side goes into the shift cable area, port side into water-jacket from pump to engine.
Just pull the drive and You get the picture, and hopefully find the inside plate/nut."
 
I unscrewed mine thinking the

I unscrewed mine thinking the gear oil would drain faster.Had the nut removed and never touched it again. The shop told me that OMC uses these holes to pressure test the lower unit. Puts the screws in it and slaps on the OMC sticker. Not one word in the manuel about them...
 
The support plates have nothin

The support plates have nothing to do with the screw(s). They take the side-load off the the pivot pins and gimball of the drive. The locking rings #62 have a tendency of cracking and fall off which make the support plates disappear as well.
 
"Hey my OMC had the same probl

"Hey my OMC had the same problem with the hole in the side, my fix was a bilge plug, but a normal 1" plug will not work, it isn't tight enough, so I took two small washers and put one on each side of the rubber plug and then screwed the retainer washer back on, tighten down and it will never come out unless you take it out"
 
Back
Top