Water leaking from spark plugs

[Hukeedo]

I got a 1970 Mercury 500. I may have been ripped off when I traded a guy for my 35HPto this 50HP. Two things I hope soemone can help with.
It starts and runs fine. Perfect in fact. But i noticed some water bubbling out from the spark plugs while it is running. has good compression in all cylinders.
I'm thinking Water jacket gasket? If thats what it is, are they hard to replace?
Should i not run the motor in this condition?

Also, the water is coming out a perfect round hole in the bottom of the block where i think a pisser spout should go, but the spout is not there, could it have fallen out?

Thanks for any help. I would like to run it and keep it as it starts and runs perfect!

 

[ChrisfromVT]

Re: Water leaking from spark plugs

Yes, water jacket gasket. I just replaced this on my 115 tower. I sprayed the bolts for the cover days in advance with penetrating oil and didn't break any, but be careful. I wouldn't run it until you fix especially if water is intruding into the combustion chamber...your plugs will indicate if their getting wet. Gaskets are cheap...motors are pricey.
Good luck

 

[nickh]

Re: Water leaking from spark plugs

I agree - water jacket. I just did this on my 1969 650. Same symptoms - I pulled the powerhead, and soaked all the bolts in PB BLast. I broke all but one I wound up drilling them out and using a heli-coil on the very bottom one. I couldn't locate a gasket anywhere locally, so I risked RTV. I had the boat out all weekend, and no issues at all. It's not too bad of a job...

 

[Hukeedo]

Re: Water leaking from spark plugs

Thanks guys, thats what i figured. I'm gonna take it to the local repair shop to have it done I think.

 

[section8]

Re: Water leaking from spark plugs

everyone working on their boats should have one of those thingys that you hit the back with a hammer to turn bolts. mine has a 1/2 inch socket head on it and an adapter for crew bits. they are a must have. i took like 20 bolts off my motors exhaust divider plate today. not one broke on a 1989. they were so stuck i wouldve broken some with just a ratchet or breaker bar!

 

[nathanhooper]

Re: Water leaking from spark plugs

I have always wondered about those tools. I have been curious to know if they could damage the block by striking the end so hard. Am I just thinking that the block is not as tough as it really is?

 

[verado7]

Re: Water leaking from spark plugs

dont ever use one of those tools that "section8" described ,on your motor .

 

[sschefer]

Re: Water leaking from spark plugs

dont ever use one of those tools that "section8" described ,on your motor .

They're called impact drivers. They were manual long before they were pneumatic. Not a good choice of tools around cast aluminum.

 

[Chris1956]

Re: Water leaking from spark plugs

Hey Huckeedo, Dry out the motor and put some caulk around the plugs to stop the leak. No water will leak into the combustion chamber, unless the block is cracked, and then you have real problems.

 

[Hackamore]

Re: Water leaking from spark plugs

Could also be a blown head gasket. Blown between water channels and cylinder. If you us an impact driver and you have conderns use a smaller hammer, You don't have to blast the heck from it. I use on with great results.

 

[Hukeedo]

Re: Water leaking from spark plugs

Yea i was wondering if i put some goop around the plugs and just run it. But if it's coming out the spark plugs, would'nt it be getting into the cylinders too?

 

[Chris1956]

Re: Water leaking from spark plugs

The seam on the water jacket cover to the cylinder head is just around the spark plug holes. If the water is coming out of the cylinder, you have a cracked block. If water is coming out of the seam of the cover and cylinder head, it is pretty common, and caulk will fix it.

 

[Chris1956]

Re: Water leaking from spark plugs

One more thing, it is possible for the inner water jacket cover under the exhaust cover to leak such that water gets into the cylinder. Normally it is a fine mist of water, not any liquid to speak of. if you have liquid water coming out the plug hole, you have a water jacket cover gasket leak as described, or a cracked block.