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Water top #4. ?

M

Mikey N.C.

Advanced Contributor
Shop I'm at , put in jasper. Long block. In 2015 . has water mixed oil. Full. My pump bucket full..pulled sp. plugs #4 on starboard side pumping water. Did leak down test . not losing .i snatched off manifold on starboard side . I could see obviously the exhaust valves . all valve stems were rusty looking. Only 1 bank.. Can only be head or head gasket or exhaust manifold rite?
If intake I'd get more than one wet cylinder rite.
Now I do have mixed oil.
 
I made plate today to seal , elbow connection. And going to pressurize manifold don't know if that's the best way ? Do I need to throw torch to it ?
 
Fwc , sea water pump at crank, that pulls from lower unit. Original Volvo-Penta manifolds.
I blocked off the 2 water outlets on thermo. housing to exhaust. manifolds removed sea water pump hose at thermo. housing connected another hose , filled block with water thru that hose hooked up radiator pressure tester pumped up to 17-19 psi. No leak down after 30 mins. Made a 3/8 " thick rubber gasket with just elbow bolt holes drilled out. Mounted elbow back on removed manifold , filled with water and pressure tested at 17-19 psi. No leaks or leak down.. Does that intake have coolant passages in the center by carb. ?
 
Because motor only had water on top of #4. Motor has 150-160 psi on all cylinders.
The 5 or 6 I done last year ( not winterized) were making oil not hydraulic locking.. And those intake manifolds were cracked on bottom side at the front and were dumping water in valley on balance shaft,cam shaft and push tubes.
 
If I had. Small head gasket water leak to #4 piston, would not compression blow out compression ring on head gasket and create a path?
 
Mikey N.C. said:
Fwc , sea water pump at crank, that pulls from lower unit. Original Volvo-Penta manifolds.
I blocked off the 2 water outlets on thermo. housing to exhaust. manifolds removed sea water pump hose at thermo. housing connected another hose , filled block with water thru that hose hooked up radiator pressure tester pumped up to 17-19 psi. No leak down after 30 mins. Made a 3/8 " thick rubber gasket with just elbow bolt holes drilled out. Mounted elbow back on removed manifold , filled with water and pressure tested at 17-19 psi. No leaks or leak down.. Does that intake have coolant passages in the center by carb. ?
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Since you are FWC, your engine has two distinct water systems. The block and heat exchanger are filled with an antifreeze mix, while the exhaust manifold ( I believe) has sea water in it ( after it runs thru the raw water side of the heat exchanger.). If the injection hole in the manifold/elbow ( where the used heated raw water is injected into the exhaust stream to exit the boat) corrodes enough, you will get sea water back down into the exhaust ports themselves ( typically the center onea if manifolds are center rise). Sea water cooled manifolds and elbows have a limited life. Since you say these are original, I'd look there.
 
My bad. It doesn't have a closed water system. It pulls water from lake to cool motor.
Fixed . It was elbow-riser on starboard side gasket. Was a thin metal gasket.
Leaking in center ,which leaks water on top of #4 cylinders exhaust valve. Replaced elbow gasket with graphite thick gasket , ran motor no more making oil, changed oil and filter 2 times. Clear as a bell.
 
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