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Freeze out plug 1977 OMC

A

Alan S

Contributing Member
I hooked up a garden hose to start the engine (990230G) after the boat was sitting for about 8 years and saw water coming out of freeze out plug under engine mount on the starboard side. Do I have to pull the engine out to replace it? And any advise on the project? Thanks, Alan
 
It all depends on access. In other words can you easily reach there to work?
It's a 1977 boat, access used to be much better than later style boats.
 
It is hidden behind the mount I can take a picture. There is only about 3/4 inch clearance I think. But when the cover is off the engine I can get right there. I just don't think I can get any tools in there.
 
Does your engine have "Selectric" trim? In other words, hydraulic trim built into the motor mount?
If yes, run the trim bow down (engine goes full up). Is there room to place blocking under the oil pan or front pulley to support the engine & remove the mount?
If no trim, can you hoist the engine enough to remove the mount?

If you feel like there won't be enough room to work, then pull the engine. Just replacing a freeze plug should be quick after you have access. Probably can work it with engine lifted but inside the boat.

Removing the engine in theory can be done without removing the intermediate drive but the outdrive needs to be off or blocked so it isn't placing any weight on the housing.

I have never done it that way, I always pull the engine & intermediate as an assembly. Probably time for a new transom seal.

Most likely the drive shaft splines to the engine coupler have never been greased & now is the time.
 
Great idea, thanks. Yes it does have the select trim, in fact I think that is what is in the way. Currently it doesn't work. I will try to figure out what is wrong with that first. Thank you, Alan
 
Droid, the trim motor works in one direction but not the other. I can see the little hydraulic rods extended from the mounts about 4 inches so I assume this is stuck in the up position. I do hear the solenoid click when I flip the switch in the other direction but I don't hear the motor run in that direction. Any advice?
 
We switched the wires from the one solenoid to the other and now it put the engine down. I tried to jump from the switch to the little wire and the solenoid did not work but I think it still clicked. We are going to switch out the solenoid to and auto one we have laying around just to test and see it it works.
 
Part shows 979774, same part number in tilt circuit. Only 1 small stud on the solenoid. Most auto have 2. If you try it, be sure to connect to the "s" terminal. Should be in same location as yours. Or better yet, swap out a tilt solenoid & order the correct part.
 
The small studs on the solenoid are wired differently so it probably won't operate.
Just jumper across the 2 big studs to do your project.
 
Droid said:
The small studs on the solenoid are wired differently so it probably won't operate.
Just jumper across the 2 big studs to do your project.
Click to expand...
The automotive one didn't seem to work. When I jumped it like you said it works. Is there any harm in letting it set down on wood blocks for a week until I get the parts. Also I will take the hydraulic line off to get that engine mount and tilt cylinder off. Any thing to be aware of with these?
 
I'm sure letting it sit will be OK.

I've owned 5 of these Fossil Drives (2 currently) but the only select trim one I had was an inline 4. The trim is a different unit so I have no experience dissecting the hydraulic type.
 
I just realized that the select trim mount is attached to the other side with a tie bar that goes under the engine. So I can't get just one side off. I think I will have to pull the engine. Anything to be especially careful when doing this?
 
I assume you have truecourse steering (steering cable hooks to intermediate housing below RH manifold).

If so & if you are removing the entire assembly, you will need to carefully disconnect the steering cable from the intermediate.

If you TRY to remove engine only it is entirely possible that the "not greased for 49 years" drive shaft to engine coupler splines will be very uncooperative. That is why I say "TRY to remove" above.
 
Yes the manual says true course steering. Ok, I will try to just lift enough to get it apart. I better wait until I have the freeze out plugs ready to go so I can do this all at once.
 
FYI, here is why I said try.....
Old 120hp intermediate would not separate from engine. Splines stuck like glue.

Had to remove bottom access panel from intermediate. Working thru the limited access with a deep offset wrench (5/8 or maybe 11/16, can't remember) I was able to remove the 6 bolts securing the coupler to flywheel (actually they hold flywheel on too) slowly, like 1/6th turn at a time. Then removed the assembly with stuck on coupler. Required a gear puller to free coupler. Cleaned splines, they were actually good. Reinstalled coupler to flywheel. Lubed splines with Molylube & reattached intermediate.
 

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If you carefully lift engine up & forward enough to gain access you'll probably be OK. Don't damage that steering cable!
 
I didn't realize I could unbolt the trim and retract them. Thanks for pushing not to remove engine. I am going to try to lift the engine a little because the trim bracket is still slightly in the way.
 
there is some gravely rust I could feel inside the engine where the plug was. should I try to remedy this some how?
 
Thank you for your patience with all my questions. Should I loose or detach those back engine mounts to try to lift it a little?
 
Wire brush on a drill to remove heavy rust.
I assume the replacement plugs are brass or stainless. Not automotive zinc plated steel.
Did the bad one freeze/push out or rust away? If rust, others are soon to follow.
You could perhaps gain 1" or so by loosening the rear. Careful not to tear the transom seal.
 
The freeze out plugs look like they are all original, I don't see where this guy replace any. This one was brass and it looks ok but I think the engine rusted around it. A few others look like they are pushing with some rust around them I guess I should try to replace those as you say they are soon to follow. Just wondering what to use to push them in. I don't know if I can swing a hammer in that small a space with any momentum. I was thinking of trying to hose that rust out with the freeze out plug still out. Are the freeze out plugs at a low point in the cooling system? Should I replace the transom seal even it it looks ok?
 
The plug has a part #1510SC stamped in it. I could not find this part # on marine engines. Also I could not find it in the parts diagram but I was not sure which parts section to look at.
 
I pulled out some old OMC parts books & freeze plugs are not shown.

Since Mercruiser used 302 & 351 blocks in the 70s, I looked there.
Mercury P/N 19-56102, 1 1/2" brass. No longer available. Maybe an ebay search? Maybe a good auto parts store that is willing to search for brass plugs?

The 1510SC part number you found would suggest to me 1.5" so that is consistent with Mercury Marine.
 
Thanks I found them on e-bay. That # you gave me helped me find it. The picture had the number I had stamped in it.
 
Lol. My father in law was a machinist and one of his favorite sayings was I would be the best mechanic in the world if I had a third arm.
 
Droid, I am still waiting for the freeze out plugs to be delivered.
I took three freeze out plugs out on the starboard side. The one that was leaking was on that side, and the other two on that side were corroded and looked like they were pushing. The other side plugs look brand new.
There was a lot of scaling rust in there I took what I could out with a magnet. I took the hose off the end that comes from the water pump and there was some scale in there as well at the elbow. I am wondering if the whole engine is like this, am I wasting my time putting it back together at this point. How big are the holes for the cooling water around the engine? I'm wondering if this scale will plug it up. I guess I could put it together and see if it overheats. It was overheating when I last used it, but I thought maybe the water pump or impeller were bad so I did replace them.
While the plugs are out I thought about using a garden hose to try to push some scale out the plug holes.
Thank you for any advice, Alan
 
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