Re: water comming out around sparkplugs Merc 19711350
OK, just to be clear; your motor got very hot, hot enough to cause smoke to come off it. That's not a Good Thing. First you need to see if your motor is Hurt, that's the reason for the suggestion of checking compression. If compression is bad, there's no sense trying to fix a water leak.
If you have decent compression readings (less than 10 psi difference between cylinders), your motor probably isn't hurt too bad.
Now, you can attack the other immediate problem, what caused it to overheat?
Always when you have a overheating problem on an outboard, you're gonna want to pull the lower unit and check the rubber impeller. Generally, unless it's just been replaced, you'll want to renew it as a matter of course. May as well while the lower unit's down.
If you don't find anything wrong with the water pump, next I'd blow air up the copper water tube and even flow water up there to check for proper circulation thru the powerhead. Just use a screw-type hose clamp to fasten a section of hose to the copper water supply tube, and adapt to your garden hose. If you have a lot of water pressure at your home, don't turn the faucet on full blast. These cooling systems are designed for 15psi max and typically only see about 12 or less.
Once you establish good water flow thru the powerhead, you can work on your leaks. Quick fix on the back cover is to clean/degrease the holes and spark plugs, then seal the area with RTV. Use automotive black or Hi-Temp red. The permanent fix is to remove the back cyl block cover (water jacket cover) and replace the gasket.
The caveat there is, if the bolts are stuck, you have to use heat (like a propane or MAPP torch) to help loosen the bolts. Otherwise, you're gonna break bolts and that's not Fun! It's a ton easier to do this with the powerhead off, but it is possible to work on the back cover in place. You'll need to remove the support brackets for the motor's lower cowling, this'll also allow the cowling to slip down a bit for access to the bottom bolts of the cover.
Clean/scrape all gasket debris from cyl block and cover with a sharp gasket scraper or razor-bladed-type paint scraper. I use an inexpensive razor-blade scraper from Wal-Mart, it's wide enough so it doesn't dig into the metal, and new blades are cheap. You can also get spray-on gasket remover to help soften up the old gaskets. The stuff also does a great job on paint so be careful with that.
Apply a VERY thin coating of RTV to the spark plug hole "pads" on the block, and on the same areas of the cover. If your replacement gasket is coated you don't need any kind of sealer on the outer edges. If it isn't coated, use Permatex #3 Aviation-Type Non-Hardening gasket dressing. It's the best stuff and remains flexible for a long time. Put a thin coat of Permatex on the cover bolts and they'll never be hard to remove again.
The cover bolts are torqued to 70 in-lbs, if you don't have a torque wrench, snug them up with a small ratchet, just don't over-tighten.
While you're at it, check the tightness of your exhaust manifold (side cover) bolts. The overheating incident will probably have loosened them up or stressed the gaskets, you don't want a leak to start there! Those bolts (if they aren't stuck) are supposed to be tightened to 150 in-lb. You likely won't be able to reach the very bottom bolts without pulling the powerhead, but checking/tightening all the ones you can get at is better than nothing.
Anyway, there it is in a Nutshell. But check the health of the motor first, before you do a bunch of $$$ other work to it. No sense sending Good Money after Bad.
HTH & let us know how it turns out............ed
