99 Merc V6 - Freeze plug falls out?

I'm not a boat engine mechanic. I enjoy saltwater fishing. I'm mechanically inclined, and finacially challanged. I'm looking at a well used 24' Stamas cuddycabin that's re-powered with a V-6 Merc. I'm told it's a 1999. Seller tells me that one of the freeze plugs "fell out" of the engine late last year when he was about to set her up for the winter. He showed me the plug. It appeared to be brass, and corrosion was minimal. There was little scarring along the rim where it was pressed into the block. Oil is not contaminated. I believe it's set up on a raw water cooling loop. Seller has owned the boat two years. Prior to him trailering the boat, it was docked in brackish water. What would cause a plug to come out (not freezing weather), and since it's on the bottom of the block, and will the engine have to be pulled to get it replaced? What else should I worry about if the freeze plug just fell out?

Re: 99 Merc V6 - Freeze plug falls out?

Howdy,


1st rule in talking to sellers........DON'T BELIEVE SELLERS!

Now having said that,

"CORE" PLUGS (also commonly & mistakenly called "Freeze plugs") usually are PUSHED out by residual water left in the block when it FREEZES.

When they "pop" out, the cast iron block frequently also cracks.

The core plugs don't protect blocks from cracking. They're there to fill holes left in the block as a result of the casting process.

Sometimes they come out due to corrosion of the hole or maybe (if you're lucky) because they weren't pushed in all the way etc.....

There's very little water pressure in the cooling system of a raw water cooled engine.

If you're thinking about buying the boat, you should thoroughly inspect the engine and maybe even pressure check the cooling system before you buy.



Regards, AND welcome to iBoats!


Rick

Re: 99 Merc V6 - Freeze plug falls out?

What would cause a plug to come out (not freezing weather), and since it's on the bottom of the block, and will the engine have to be pulled to get it replaced? What else should I worry about if the freeze plug just fell out?

Click to expand...

Ayuh,... Echoin' what Rick said,... Core plugs don't "Just" fall out...
They're pushed out by Freezing Water,...
No other reasons...
Yes, the motor may have to be pulled to replace it...
Other Problems, could well be a Cracked block....

I'd look for a Different boat...

Re: 99 Merc V6 - Freeze plug falls out?

Have to agree, the water left in the block froze and pushed the plug out.Maybe 1% or less suffer no damage.You can have the PO have it reinstalled and then see if the motor is still ok.Can install some type of temporary plug, (rags) and try running the motor and check for any leaks or oil contamination.
The odd`s are stacked against it though.

Re: 99 Merc V6 - Freeze plug falls out?

I have to agree with the above replies.
If it was such a simple job to just reinstall the plug and everything is fine, why wouldn't the owner get it pushed back in and not worry about it?
Reason is simple, he knows the engine froze, and doesn't want to deal with it. Wants to just make it sound like a simple easy job and all YOU have to do is push the plug in and all is well.
You could put in a rubber expansion plug without pulling the engine and then do an on the water test run to see if the block is cracked. The reason you test it on the water, is you get more water flow and pressure than you will on muffs. Then you will see if you get water in the oil. I have seen several engines that worked great on the hose, but the crankcase filled with oil when on the water.

Personally, I would run away from that boat, and keep looking.

One other note, a V6 in a 24' boat is way underpowered.

Re: 99 Merc V6 - Freeze plug falls out?

While I agree with everyone on the engine issue, there is an opportunity here to score a deal. Explain to the seller that you don't believe his story and that you suspect the block froze and popped the plug which means there is a high likelyhood that the block is cracked. The only way to prove or disprove that is to install a rubber expansion plug ( couple of bucks at any auto store). You can offer to buy the plug and install it. Now then -- here's the deal: 1) Do an on-water test lasting at least 30 minutes with at least five minutes of WOT operation. Check the oil before and after the test. Water present = block is cracked and your offer is $xxxx.00 with that number based on the full cost of a rebuilt engine installation with an additional discount for your trouble (and make it worth your while). Make sure you do some checking as to the costs in your area for the engine replacement. 2) No water present, the engine is likely ok, but still suspect and your offer is $yyyy.00. If you don't want to be bothered, run away from it.

Re: 99 Merc V6 - Freeze plug falls out?

Even if the block isn't cracked there is no way I would buy a 24' boat with a V6

Re: 99 Merc V6 - Freeze plug falls out?

Silvertip said:

While I agree with everyone on the engine issue, there is an opportunity here to score a deal. Explain to the seller that you don't believe his story and that you suspect the block froze and popped the plug which means there is a high likelyhood that the block is cracked.

Click to expand...

Ayuh,.... Offer the guy pennies on a Dollar, as a Dead boat is a liability, not an asset...

Take it off his hands, 'n drop in a brand new/ used 350, 'n Go Boatin'.....

Re: 99 Merc V6 - Freeze plug falls out?

Take it off his hands, 'n drop in a brand new/ used 350, 'n Go Boatin'.....[/QUOTE]

First, let me thank each of you for the great advice. I appreciate the responses, and you've helped me avoid lot's of headaches. I was suspious of the cracked block, but had no idea she would be underpowered. The boat's a couple hour drive from me, so running tests would be difficult logistically. I'm going to keep looking, and check around for what a 350 replacement would run, just in case the guy would be willing to unload a "likely" dead boat. Thanks again, you guys have made a believer out of me with this forum. Now, for the obvious question, what's a good $$ budget to expect for a re-power with the suggested 350? For reference, and if it matters, I'm on the eastern shore peninsula of Virginia.

Re: 99 Merc V6 - Freeze plug falls out?

Keep looking. There are deals all over the Hampton roads area. I bought 9 boats last year for next to nothing...