water in left 4 cylinder of gm350

BrentW

Cadet
Joined
Feb 3, 2010
Messages
11
im looking for some ideas as to how i have water in my left cylinders of v8 engine. im getting ready to pull the manifold, riser and head from that side. what could be the cause of this. water jackets, heads,?????? i had taken boat out and it ran pretty good but near end of an hour plus run it became hard to start and i ended up burning starter up trying to restart.so i brung boat home and it sat untouched for 4 days. now on the 4th day when replacment starter showed up i installed. at this time engine seemed liked it didnt want to turn over very easy. then on 3rd turn of the key i heard a deep metal clunk, and at that time i stopped and was like that did not sound so good. im thinking a broken rod but not sure yet. but anyway at that time i pulled one of the spark plugs and water just come pouring out. now at this time im scrapping my heart up off the bottom of the boats floor. but i went ahead and unscrewed drain plugs on manifolds and risers and then all the plugs and turned motor over to push water out. motor turned over but did not sound so hot. anyway thats where i stand as of right now. im thinking of going out there now and sprying some pb blaster in the cylinders and cranking over a few times. i know this is going to lead to removeal of engine but any ideas of to the cause is great. ive got my ideas but other insight is what im also looking for. im thinking something with the heads. i had ran engine several times in a 55 gal. before i took it out in the bay and had no problems. granted it did not reach the temps. that i got it to out on the bay. but when i had it running on the water in drum it had water flowing through it with no appernt leaks or problems. could it of been thed salt water that i left sitting in it for 4 days after the starter. im going out now to start ripping apart i guess.
 

John_S

Rear Admiral
Joined
Jun 21, 2004
Messages
4,269
Re: water in left 4 cylinder of gm350

Most likely rusted or leaking exhaust manifold or riser gaskets. I don't know how much rust would set-up in four days, but with salt water, probably not pretty. If the valves rusted and are lucky, the clunk was just push rod bending. Hydro-lock can break rods and pistons.
 

bigskiohio

Master Chief Petty Officer
Joined
May 3, 2008
Messages
882
Re: water in left 4 cylinder of gm350

anytime you here a clunk when starting and it wont go hydrolock is the problem or mechanical failure . Head gasket ,i would say then manifold or riser unless you dont have the flappers and you backed off on throttle quick and the water came back. should always come down slow off wide open and let it idle before shutting off. my 2 cents.
 

wire2

Lieutenant Commander
Joined
Jun 25, 2007
Messages
1,584
Re: water in left 4 cylinder of gm350

Can do a basic compression test by putting a finger over the spark plug hole & have someone "start" at the key. A broken rod cyl will have no "puff" of air.
 

BrentW

Cadet
Joined
Feb 3, 2010
Messages
11
Re: water in left 4 cylinder of gm350

well good thing is i do not think i broke a rod. i have compression in all cylinders. my manifolds and risers are brand new. now i have an alpha 1 outdrive raw water pickup coming from impeller in the outdrive and the water pump of course. my first question is does anyone know what gaskets i should use for the risers. i used the one supplied and never thought twice about it. it was the one that has two openings. now, ive seen some with no openings and some with the four openings. and like i said i used the ones that have the two opening slots. ive got 4" middle risers and manifolds that are mercruiser v8 5.7. the head gasket was brand new and tourqed correctly. im down to guessing the flappers in the exhaust failed, but then im thinking the boat only stalled during low speed through a no wake. so i didnt let suddenly off gas at highspeed. so that brought me to thinking its the water jackets in the left head. the heads came off a 1989 merc 5.7 that had some kind of water damage but i just do not know what kind. but i took the heads to a speed shop that does boat work and had the heads plained and looked over. but how can you tell if the jackets have holes. you wqould have to pressure test right? i just pulled the valve covers off and on both sides in the rear there is a white colored substance that looks like oil and water mixture. any ideas on that... more and more im leaning toward the heads being bad. but would that cause water to fill plug holes.. im going outside to investigate more right now before completly dark
 

TilliamWe

Banned
Joined
Dec 21, 2004
Messages
6,579
Re: water in left 4 cylinder of gm350

Water in cylinders (especially all the ones on one side) in a marine engine is an exhaust manifold and/or riser issue.
 
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