Water in Engine

[62cruiserinc]

A couple of days ago my son took out our 1981 Sea Ray 260 Sundancer (5.7L with Alpha Drive).


This is what he says happened:

He got out onto the lake, shut off the engine, and went swimming with his buddy.

The engine wouldn't re-start. He tried cranking it about 7 or 8 times (it turned over but it didn't start) and then the starter made a noise which indicated it was spinning but not engaging the teeth. He got a tow to the dock (about 3 miles from where he was).

I tried the starter this morning and it was spinning but not turning the engine over. Went to the local boat store, got a new starter, and installed it. The new starter engaged, but the engine only turned over a tiny bit (a few degrees) and bounced back to the original position, like something was keeping it from turning.

First thing I thought was water hydrolock. We removed the 8 spark plugs (which had water on them). Now the engine turned over easily and blew water out the spark plug holes. We did this about 12 times until no water blew out. We replaced the spark plugs and the engine started and ran fine.

What happened? Did the towing cause water to enter through the exhaust? Does this mean the exhaust shutters are bad? I asked if he had gone hard throttle and then cut the throttle back to idle and he admitted he did (he didn't know this was bad).

I looked online and couldn't find a diagram that showed where the shutters are on my boat. I have the risers at the back of the motor that directly exit straight downward to the rubber (3" to 4" inch adapters to the Y-tube) connectors. Are the shutters in the rubber part?

Any ideas on what happened here? I want to fix any possible bad parts before I go out again.

Thanks
Steve

 

[dubs283]

40 year old boat with original engine/drive, equipment, etc...?

You keep up with routine maintenance?

 

[62cruiserinc]

I bought the boat 6 years ago.

The previous owner put in a a crate engine replacement and the outdrive is an SEI replacement for the alpha. It was well maintained by the previous owner. I also keep up on the maintenance (replaced pump, bellows, oil, etc.

I have not done anything with the exhaust manifolds or the shutters since I bought it.

Steve

 

[tpenfield]

A bit of a guessing game, but I'll share my thoughts.

Probably not the exhaust shutters, as they never give a water tight seal anyway.

More likely the exhaust manifolds are leaking (or possibly the intake manifold). Anyway, it would be best to determine the culprit and address accordingly.

 

[Scott06]

Agree with ted i would be verifying there are no leaks On exhuast manifolds elbows and risers . I would think based off your comments it hydro locked while they were swimming.

other thing pressure test cooling system if you dont find issue with exhaust.

now that you have it running make sure there is no water in the oil from the hydro lock , may need to change it a couple times .

 

[alldodge]

Don't know what boat, but if the boat is small and light and everyone is sitting on the stern, water can flow back into the exhaust elbow.

 

[dubs283]

Failure of water shutters could very well be the cause of your hydrolock, especially since both sides were affected. This does not rule out failed manifolds/risers on both sides either.

With log style manifolds, which I'm guessing you have given the vintage, the shutters are located near the bottom of the y pipe and not easily inspected/replaced

 

[62cruiserinc]

Thanks for the ideas.

What are the odds that BOTH exhaust manifolds/risers failed at the same time?

What are log-style manifolds (as someone mentioned)? My manifolds are rectangular cross section. I will try to get a picture posted later.

How do you pressure-test the cooling system? I have an automotive cooling system pressure tester. Would I disconnect the hose from the outdrive and apply the pressure there?

My boat is a 26' cruiser that weighs a out 6500 lbs (if I remember correctly).

I guess I will have to take off the risers and see if I can look at the shutters. I have a borescope camera if I need to look down the Y-pipe.

I will probably have to buy a bunch of gaskets if I start to take apart everything.

How do you check the risers and manifolds once they are removed? A visual inspection?

Thanks again,
Steve

 

[Lou C]

The manifolds can be inspected by propping them up level & filling with Acetone (careful very flammable) it will leak through cracks that water might not.