Water in cylinders

[cvargas175]

Hey everyone,
So I'm lost and need some good guidance. I have a 4.3 Mercruiser that hydrolocked on me the last time I had the boat out. It ran well this season other than stalling when I slowed down. I brought it home and replaced the starter as a result of the hydrolock. I removed the spark plugs and cranked the motor to remove the water. Some water came from both sides but not sure if from all 6 cylinders. I checked the water shutters and need to replace them. The thing is the engine runs but bogs down as soon as I turn on the water to the ears which obviously means the water is getting in from elsewhere other than the exhaust. I'm really hoping I don't have a cracked block. How do I diagnose a bad head gasket or something else like the exhaust manifolds. I removed the manifolds already and didn't notice any rusty water. I can do most of the work myself with some professional guidance. I appreciate any help and thanks in advance!

 

[Bondo]

Ayuh,.... Welcome Aboard,..... The 4.3l has been used in 100s of configurations,... Got a serial number,..??
Carbed,..??
Efi,..??
'bout what year,..??

Are the exhaust manifolds still off the motor,..??
If ya isolate the block, pluggin' hoses, then pressurize with air, you hear the leak, follow the sound,...
Could be a cracked intake manifold maybe,....

 

[Scott Danforth]

Could be manifold to elbow joint
Could be cracked manifolds
Could be cracked intake
Could be cracked block
May be head gasket

 

[tpenfield]

Since you got water on both sides of the engine, my vote gets the intake manifold having a crack or perforation which is allowing water directly into the intake.

Tell us more about the engine though, with little information, it is pretty much a guessing game.

 

[Lou C]

Cracked heads and blocks are difficult to diagnose without dis assembly because they don't always cause water leaks. I had cracks in both heads (center cyls exhaust ports) but no water leaks from there. I had 2 blown HGs one put water in cyl # 2 the other just put a trace of water in cyl # 1. The compression test results were normal. If I blew out the water the engine ran normally and would not show water in the cyls till it sat for a day or so. When I took it apart both HGs were blown where the fire ring is bonded to the main part of the gasket, just slit at the seam. So do a comp test and air pressure test. I rigged up a way to test for combustion gas getting into the cooling water using extra hose and funnels. And what it showed was that combustion gas was getting into the cooling water right after the engine was shut off. So then it stood to reason that the reverse could also happen. But until you take it apart you won't know if it's the intake, HGs or cracks. Cracks are very difficult to see I took my old heads to a machine shop that's how I found out that. But the water really came from the HGs.

 

[cvargas175]

Thanks guys for the prompt response. I have a 2005 4.3 Mercruiser with carburetor turn key system. Serial #0w353864. Yes Bondo the manifolds are still out. I would obviously like to diagnose as much as possible without tearing the engine apart via process of elimination.

 

[Bondo]

I would obviously like to diagnose as much as possible without tearing the engine apart via process of elimination.

Ayuh,.... Then drain the block, isolate it, 'n pressurize it with air, you'll hear the leak, follow the sound,....