Water coming from spark plug hole inline 6 following overheat

[zcapogna]

Welp, I was on the homerun stretch of rebuilding 1986 Mariner inline 6 90HP tower of ppower. Ran it up using a homemade test tank while doing idle adjustments I finally noticed water level had dropped in the tank for a minute or so. I should have let her cool down but like a dummy, I started it back up and continued the adjustments. All seemed okay but fuel pressure was low so ordered and rebuilt the fuel pump...

...started back up today and running rich/won't idle. While inspecting, noticed water coming near the bottom spark plug threads. My first thought...I cracked the head. I did a compression test and still 120PSI.

Any advice on what I did?

 

[zcapogna]

Here is a picture. After additional researxh, i think it might just be the gasket. Not sure why it went bad in conjunction with the extra heat but that appears to be the case. Engine runs same and all cylinders are firing.

Appreciate any comments from the gurus here.

 

[Scott Danforth]

Pull the cooling water cover and inspect the gasket surfaces

 

[racerone]

Agreed -----Replace that water jacket gasket

 

[zcapogna]

Thanks for the advice. Got it off, and all bolts broke free no issue. Gasket will be ordered soon. I really thought I'd cracked something...glad it's just a gasket.

 

[Chris1956]

If the bolts came out, you have a fresh water only motor. Congrats on that.

Salty motors usually break all but the very bottom bolts, for some reason.

 

[jimmbo]

If you overheated the engine, the Cover Plate likely warped, and a new gasket will only seal for a bit. That happened on my 84 115 back in the mid 80s. After replacing the gasket 3 times, sometimes Dry, other times with sealer, the Service Manager at the dealer, gave me a new Cover, no more leak.

 

[zcapogna]

Yupper Chris1956. I'm restoring an 86 Fresh Only tower of power. Slow going but getting there.

Roger copy Jimmbo. I think I'll be okay. It was only without water for a short time.

Will let you know!

 

[zcapogna]

About to start scrapping the 40-year old paper gasket off. Read to stay away from Scotch bright-type pads on grinders/dremmel for aluminum mating surfaces and to stick with acetone and a razer blade.

Anyone know if the cooling jacket is made of aluminum...also any gasket removal tips and/or tricks?

 

[racerone]

There are some spray on gasket softeners.----Yes the block is aluminum.-----In the hands of a careful worker even a sturdy paint scraper will remove gaskets with no damage to aluminum.----Brushing some oil on the gasket may soften it up.

 

[zcapogna]

There are some spray on gasket softeners.----Yes the block is aluminum.-----In the hands of a careful worker even a sturdy paint scraper will remove gaskets with no damage to aluminum.----Brushing some oil on the gasket may soften it up.

Thanks racerone. I went slow and used combo of alcohol, WD40, plastic scrapers, and a sharp razer blade. Fingers crossed I got a good seal.

 

[jimmbo]

Looks good. Hope you remembered that last bolt at the bottom

 

[zcapogna]

Looks good. Hope you remembered that last bolt at the bottom

Lol jimmbo. I took it out today for a run at the dock and discovered the missing bolt. Good thing I bought a few extras.