M440 suddenly locked up with water

[lbarnes88]

"My continuing saga with a &#3

"My continuing saga with a '71 M440. Over the weekend, I had my Century Coronado at the dock, in the water for several hours. It was a busy day, lots of boat wakes and waves.... It ran fine earlier that day. I went to start it, and it was locked up solid, would not turn, and did not start. I removed all spark plugs and cranked it over. One of the rear cylinders was in fact, full of water. So I turned it over a few more times to dry it out. Then I put the plugs back in, checked the oil, and it started right up. Seemed to run OK. I assume it took in a wave thru the exhaust, and got past an open valve, into a cylinder. Now I think I know why these old inboards have the rubber flapper vales on the exhaust (mine does not have them. Yet)... OK, what damage might I have done? It never started when full of water. It just would not crank. Can the starter motor alone cause a bent rod? What else should I check out?"

 

[fastjeff]

No problem for it did NOT star

No problem for it did NOT start. Do put those rubber flappers on. I run them on mine as well.

Jeff

 

[loid58]

"It could be worse than rubber

"It could be worse than rubber flappers. Sounds like your manifold is bad and leaking water into the cylinder. It will run fine, but when you shut down, the water thats in the manifold leaks right back down into the cylinder, causing the hydro lock you had. Run the motor a little then shut down and let it sit an hour or so. Pull the plug(s) see if they are wet and there is water in there. If so, you need new manifolds and risers. Also if the manifolds are 5yrs or older, you should replace them anyway. P.S if you remove the plugs and turn the motor over, be sure to remove the coil wire, could start a fire if you dont."