Replacing freeze plugs

[Travis71]

I have an 89 model OMC 5.0L that is missing two freeze plugs. I replaced one with the expandable rubber seal type, but the other one is behind the motor mount and the gap is too small to get the freeze plug into. I figure I am going to have to pull the motor to get to it unless someone on here has a better suggestion.

 

[racerone]

Any idea why these freeze plugs are not in there now ?------Best to check this engine out carefully before launching.

 

[Travis71]

I do not know. Boat sat at least 10 years without being run before I bought it. I got the engine running yesterday and it purrs like a kitten, starts right up no issues at all. I stuffed a rag in the hole to stem the flow of water a little bit just to see if it would run. Now that I know it runs I would like to address the freeze plug issue.

 

[Scott Danforth]

they are not "freeze" plugs, they are core plugs to get the core sand out of the casting at the foundry.

GM 5.0 or Ford 5.0?

if its a GM 5.0 and the core plugs are pushed out, most likely the block is cracked

if its a Ford 5.0 and the core plugs are pushed out, 50/50% chance the block survived

core plugs should not come out

 

[kenny nunez]

You might have some luck by un bolting the lag screws and with a small bottle jack you will be able to lift the engine just enough to remove the mount from the side of the engine and install the rubber plug.
Just like Scott said the Ford engines are a lot stronger because they are cast from Nodular iron. I have never seen a GM engine push out a core plug without being cracked.

 

[Scott Danforth]

also, the only reason core plugs come out of a boat motor is from lack of winterization.

 

[Travis71]

You might have some luck by un bolting the lag screws and with a small bottle jack you will be able to lift the engine just enough to remove the mount from the side of the engine and install the rubber plug.
Just like Scott said the Ford engines are a lot stronger because they are cast from Nodular iron. I have never seen a GM engine push out a core plug without being cracked.

I didn't use a bottle jack, but I did accomplish the task as you described with a large tow strap. It is a Ford 5.0 and the block seems to have survived. I have had it running and no water in the oil. I took the boat to the lake for a little test run and the engine was popping and backfiring when I put a load on it so I have some work to do there. I just toodled around near the dock for 5 minutes and put it back on the trailer. No water in the boat and nothing blew up, I am considering it a win! But I still have a ways to go before she is truly resurrected.

 

[Scott Danforth]

consider yourself lucky on the motor.

now lets hope you are that lucky with wet foam. late 80's vintage OMC branded boats (yes OMC owned many boat companies) are not known to last this long without issues