Water in oil, water spilling from #1 spark plug socket

[jlucas209]

I know now why they say BOAT = Bring out another thousand :/

I have an 1987 merc 350 5.7 competition ski, I check the oil every time before I go out, last time it was ok. Went out for the entire day and no problem.

I had been planning to change my oil so yesterday I hooked up the water connection and turn on the engine (to warm up) and went to get the supplies from autozone down the street. I return 15 min later, everything is fine idling fine and temp is good. I cut the engine and check the oil and its a milky mess, pop open valve covers openings and its like peanut butter. I just happen to notice water dripping from my #1 spark plug hole, the spark plug seemed to have loosened it self some how. I tighten it back with my fingers and attempt to start the motor again and I believe I experienced "hydrolocking" the motor didnt want to crank as if my batteries were dead but they were both fully charged. After several slow wimpy cranks it started and I immediately shut it back off.

So, it looks like my weekend boating plans are ruined. I've done alot of searching and still not positive on where to start. I've read it can be cracked block, cracked head, blown head gasket, blown riser gasket, etc...

I did continue and removed all the oil with my handpump and called it a night. So next I need to remove all the spark plugs and crank the engine to make sure all water it out of the cylinders? That will solve the hydrolocking part (praying). Then what should I diagnose next? Do a compression test or just proceed with pulling the heads since their most likely going to need to come off anyway? Any input is appreciated!!

 

[thumpar]

Pressurize the cooling system to see how the water is getting in.

 

[jlucas209]

Pressurize the cooling system to see how the water is getting in.

I'm sorry can you elaborate? I've done a cooling system pressure test on a car before but not an inboard boat motor with no rad.

 

[jlucas209]

This is a direct drive boat with an "open" cooling system, raw water cooled.

 

[Bondo]

Ayuh,..... So you drain the block, isolate the block, from everything else by removin' hoses or pluggin' hoses, or whatever it takes,....
In that process, ya plumb in an air port, 'n pressure gauge,....
Pressurize the block to 'bout 15 psi, 'n Listen,.....
Then follow the sound of air escapin', to the crack,....

 

[jlucas209]

Ayuh,..... So you drain the block, isolate the block, from everything else by removin' hoses or pluggin' hoses, or whatever it takes,....
In that process, ya plumb in an air port, 'n pressure gauge,....
Pressurize the block to 'bout 15 psi, 'n Listen,.....
Then follow the sound of air escapin', to the crack,....

To anyone that has done this before, are you really able to pinpoint where your leak is coming from? I'm having hard time trying to visualize this lol. Along with plugging/blocking off all the tubes (and exhaust pipes right?) Say its coming from the back or the front or sounds like is by the head. How will that determine my problem? Thx

 

[Bondo]

Along with plugging/blocking off all the tubes (and exhaust pipes right?)

Ayuh,..... Yer dealin' with the COOLING SYSTEM,..... Why in 'ell would you plug the exhaust,..??

When yer chasin' the sound, ya listen through the carb, the oil fill ports, the dipstick hole, the spark plug holes, 'n yes, the exhaust passages,....
Ya listen through all the holes in the motor,. that Ain't water passages,.....

 

[jlucas209]

Ayuh,..... So you drain the block, isolate the block, from everything else by removin' hoses or pluggin' hoses, or whatever it takes,....
In that process, ya plumb in an air port, 'n pressure gauge,....
Pressurize the block to 'bout 15 psi, 'n Listen,.....
Then follow the sound of air escapin', to the crack,....

Trying to get around to this today, I tried googling and youtube but cant find good directions or methods on how to do this test.

Specially "pluming in air", anyone have a easy method on doing this? I found some rubber expansion joints I plan to plug of the hoses with, hopefully those will work.

 

[scoflaw]

There should be a NPT opening on your T-stat housing . You can work off that.

 

[Rick Stephens]

To simplify this some - pull the water hoses going off the thermostat housing to the exhaust and plug them. Use a piece of broomstick, whatever, stuff in the end of those hoses and tighten the clamp. Remove the water in line at the thermostat and plug that thermostat port as well. You now have a closed cooling system limited to the block. There is a plug on the thermostat housing, pull it and plumb in a schrader valve. You can now put pressure in and listen. Don't make a big deal out of making this fancy.

 

[jlucas209]

To simplify this some - pull the water hoses going off the thermostat housing to the exhaust and plug them. Use a piece of broomstick, whatever, stuff in the end of those hoses and tighten the clamp. Remove the water in line at the thermostat and plug that thermostat port as well. You now have a closed cooling system limited to the block. There is a plug on the thermostat housing, pull it and plumb in a schrader valve. You can now put pressure in and listen. Don't make a big deal out of making this fancy.

OK so I'm going to cap off the 4 hoses marked with the X, including the water inlet of course at the back of the engine. I'm going to screw my air compressor hose directly into that plug circled, pump about 15 psi and listen for the leak? What are you referring to when you say plug the thermostat port?


Thanks!

 

[Rick Stephens]

OK so I'm going to cap off the 4 hoses marked with the X, including the water inlet of course at the back of the engine. I'm going to screw my air compressor hose directly into that plug circled, pump about 15 psi and listen for the leak? What are you referring to when you say plug the thermostat port?


Thanks!

Meaning plug the inlet port where the 'in' line comes from the transom. I find it easier to plug the nipple off the thermostat housing than to get in and disconnect from the transom. Hence I said plug the port... should of said nipple I guess.

 

[Bondo]

I'm going to screw my air compressor hose directly into that plug circled, pump about 15 psi and listen for the leak?

Ayuh,..... No need to disturb that plug circled,.....

Just rig up yer input air, into 1 one the hoses yer pluggin',......

 

[jlucas209]

Appreciate all the help guys, the test worked like a charm. Had a few trials and errors but finally got everything plugged tight enough, pumped in 15psi and listened away. I had my exhaust manifolds removed and listened closely and heard air escaping from #1 I pulled the spark plug and the piston was near TDC, the water pooled on top of the piston was dancing. Checked all other cylinders and seemed to be no noise. Pulled the head and this was my culprit. (Yes that is a newer head gasket)

 

[Rick Stephens]

Holy head job batman. That surely gives you a target to go after the repairs. This motor get hot at some point?

 

[Lou C]

In your second pic it looks like you have 2 different cracks between the intake and exhaust valve, opposite the spark plug, also looks a bit like rust through but the rest of the head pix do not show excessive rust. I'd pull the other head, have both looked over by a machine shop...probably wind up getting a set of good re-man heads...check intake carefully also...