Hydrolocked all cylinders loaded with saltwater. What happened?

[subcrx]

My 87 bayliner with its 5.7 liter cobra drive locked up on me at the launch ramp. I was on my way in from a days trip. boat ran well for the most part except for that stalling problem under load that I have been battling forever. Once I got back to the launch ramp at days end the ramp was cluttered with launch ramp idiots. So I had to circle around for a bit and wait my turn. Upon shifting into reverse the engine stalled. I could not restart it. Popped the hatch and saw the starter smoking. Figured it was that. Replaced the starter and still seized. Removed plugs and cranked over. Shot out loads of saltwater. All 8 cylinders were flooded. I got it all back together and its running fine. How did this happen? I have new manifolds and risers. I know I dont have those flaps in the exhaust tube. Are those necessary? could that be the reason for the hydro lock?

 

[Haut Medoc]

Re: Hydrolocked all cylinders loaded with saltwater. What happened?

My 87 bayliner with its 5.7 liter cobra drive locked up on me at the launch ramp. I was on my way in from a days trip. boat ran well for the most part except for that stalling problem under load that I have been battling forever. Once I got back to the launch ramp at days end the ramp was cluttered with launch ramp idiots. So I had to circle around for a bit and wait my turn. Upon shifting into reverse the engine stalled. I could not restart it. Popped the hatch and saw the starter smoking. Figured it was that. Replaced the starter and still seized. Removed plugs and cranked over. Shot out loads of saltwater. All 8 cylinders were flooded. I got it all back together and its running fine. How did this happen? I have new manifolds and risers. I know I dont have those flaps in the exhaust tube. Are those necessary? could that be the reason for the hydro lock?

It would have to diesel to get water in all 8 cylinders, but lack of shutters can affect a boat with a low static level....
(That's how high water sits in your y pipe at rest).....

 

[subcrx]

Re: Hydrolocked all cylinders loaded with saltwater. What happened?

these shutters would sit pretty low in the tubes. would they still keep water out?

 

[MikDee]

Re: Hydrolocked all cylinders loaded with saltwater. What happened?

Without shutters, I would think backing up then the engine stalling, would have a tendency of pushing water up into the Y-pipe, and if you're at idle, the static head of water would be pretty high, compounded by the fact you have no shutters. Bad boy that I am, I always ran thru-hull exhaust, with mufflers if possible it eliminates that problem, anyway.

 

[subcrx]

Re: Hydrolocked all cylinders loaded with saltwater. What happened?

yes, but if I were to install the shutters they would go really low in the pipes, just at or below the water line.

 

[crazy charlie]

Re: Hydrolocked all cylinders loaded with saltwater. What happened?

Any exhaust shutters I have seen are at the top of the y tube.That should be above water level but it depends on the boat and how many people are in the stern and how you come on and off plane.

 

[subcrx]

Re: Hydrolocked all cylinders loaded with saltwater. What happened?

Im gunna put them in. Do they have any types of springs that are supposed to go on them?

 

[Bondo]

Re: Hydrolocked all cylinders loaded with saltwater. What happened?

yes, but if I were to install the shutters they would go really low in the pipes, just at or below the water line.

Ayuh,.... It Don't Matter.....

Flappers don't actually Stop the water perse'....
They stop the Momentum of the water, Which stops the water before it normally would.....
I don't know about your OMC,..
But Merc has mounted them both in the Bottom,+ at the Top of the Y-pipe over the years...

 

[subcrx]

Re: Hydrolocked all cylinders loaded with saltwater. What happened?

I see but is there springs that hold them shut when the engine is off

 

[mylesm260]

Re: Hydrolocked all cylinders loaded with saltwater. What happened?

Uhhhuum

Is it even posible to hydrolock an engine through the exhaust?

I mean the exhaust valves are only open as the piston is comming up, and the close once the piston reaches the top, so any water in the manifold would be getting pumped OUT of the engine, not into it.

IF your engine is hydrolocking on salt water, I would have a good look at your intake manifold, I would wager you've blown a gasket and coolent has leaked in that way. Especially if you've got water in all 8 cylinders. Water getting into an engine from the exhaust just doesn't make any sense (to me anyway).

Water leaking into your intake could certainly make your engine run like a bag of crap too, might explain your stalling.

 

[subcrx]

Re: Hydrolocked all cylinders loaded with saltwater. What happened?

Uhhhuum

Is it even posible to hydrolock an engine through the exhaust?

I mean the exhaust valves are only open as the piston is comming up, and the close once the piston reaches the top, so any water in the manifold would be getting pumped OUT of the engine, not into it.

IF your engine is hydrolocking on salt water, I would have a good look at your intake manifold, I would wager you've blown a gasket and coolent has leaked in that way. Especially if you've got water in all 8 cylinders. Water getting into an engine from the exhaust just doesn't make any sense (to me anyway).

Water leaking into your intake could certainly make your engine run like a bag of crap too, might explain your stalling.

I have a closed cooling system. And when I pulled the plugs they were flooded with saltwater, not coolant. Then only way that i can think of for that much saltwater to get in there was for it to rush over the top of the risers. Does that make sense now?

 

[mylesm260]

Re: Hydrolocked all cylinders loaded with saltwater. What happened?

Well, the fact that you have a closed cooling system certainly does dis-credit my theory.

I still find it really hard to believe you could actually hydrolock an engine through the exhaust though.

How high are your risers above the water line?

 

[subcrx]

Re: Hydrolocked all cylinders loaded with saltwater. What happened?

if the valve is open when the engine shuts off anything is welcome in. Its hard to say how far they are. maybe one and a half foot above the water line

 

[MikDee]

Re: Hydrolocked all cylinders loaded with saltwater. What happened?

Re-reading your post, water in all 8 cylinders? instead of one, two, or a few, and now finding out you have a closed cooling system, Has me stumped I would more likely suspect your manifolds, & risers, if they are new, maybe they are defective? Or, I'd check out the riser surfaces, & gaskets, for a warped surface, or seawater leaks, for some reason.