Troubleshooting Question

[PVBum]

IMPORTANT NOTE: During most troubleshooting work, it is frequently necessary to turn the engine over on the starter with the engine NOT STARTING. Be sure to close the raw water thru-hull valve during these times so as to avoid filling the exhaust system with raw water until it backs up into the exhaust manifold, and into the combustion chambers of the engine.


Ok I've read the above in a few places. What exactly would the result be if the exhaust system did fill up with raw water and backed up all the way into the combustion chambers?

What if that happened and you didn't realize it and continued to try and troubleshoot?

[Flagman101]

Very bad. Water does not compress.
Piston mouvement wouldforce water trough rings, valves.
If enough gets in it could damage the engine. bend something. But most likely youd would end up with an engine with water in it and rust!
Not good not good.

[sastanley]

The engine on my boat has been drowned at least once by overcranking by the PO. THen if you don't realize you've done this, the water sits and rusts everything.

Once you free up the motor, you can do a few oil changes to remove the oil that gets into the crankcase..then you have to deal with stuck valves, & maybe stuck rings.

I don't know how my motor still runs, but I keep working on it..the lingering effects are reduced compression in cyls 3 & 4 from the rust damage.