1998 mariner offshore V135 water in cylinder

bjrrockwell

Seaman Apprentice
Joined
Jun 18, 2011
Messages
49
This all started with a low oil alarm that turned out to be a tach signal failing on all left cylinders but no alarm when on right bank. http://forums.iboats.com/showthread.php?t=506780&page=3&p=3502428 shows the thread to this. Changed plugs today while narrowing down electrical problem and noticed bootom left plug looked cleaner then the rest. ran compression check and all cylinders came in at 110psi cold except this one came in at 107. Put new plugs in and fired up on muffs for less than 2 min at idle to run some more electrical tests. pulled that plug when finished and it was gooped up with brownish mayo like substance, so obviously water getting in there. My question is where do i go next. I wanted to just winterize and store. I squirted some two cycle oil in the cylinder and cranked a few times to distribute to hopefully negate the effects of the water. What are the potential sources of this water intrusion? THank you.
 

bjrrockwell

Seaman Apprentice
Joined
Jun 18, 2011
Messages
49
Re: 1998 mariner offshore V135 water in cylinder

Also as a note the original alarm tach signal was located on the cylinder that is now getting water. Getting it even on the muffs just enough to milk up the plug so far...
 

CharlieB

Vice Admiral
Joined
Apr 10, 2007
Messages
5,617
Re: 1998 mariner offshore V135 water in cylinder

Most common cause of water in a cyl is a failing exhaust cover gasket.
 
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