Weird

[carolynrose]

Was out in my boat today. 1988 Trophy 2556, OMC 350. Ran good, put about 15 miles on it I was docking in reverse when the motor stalled. I couldn't get it started. When we checked it the motor was locked up. Both front cylinders on both banks were full of seawater. Pulled out all the plugs and cranked it over, water blew all over. Cleaned the plugs and it started up with difficulty, cleared up and ran fine. Checked every thing I could think of and found nothing. One of the guys in the marina came over and while were checking things out he noticed the spark arrester was totally clogged.

Now I've been a auto mechanic and never heard of this. He said that the engine could not breathe and sucked air from the exhaust pulling water into the engine.

I thought about it and noticed that there are no vacuum fittings or lines of any kind in the intake and wondered how the engine could run so well with the spark arrester clogged completely.

Any thoughts?

 

[Jeepster04]

Re: Weird

If salt water got into the cylinders you had best been fogging it to make sure no rust sets up. Might want to change the oil too encase any water got into the oil. Have you checked the oil?

Were you just slowly reversing? No big waves or anything? Have you checked the manifolds and risers? If youre boating in salt water its possible those are in need of replacement sooner than they would normally be.

 

[carolynrose]

Re: Weird

I checked the oil a dozen times today after the occurance to see if it got milky. It was crystal clean.

We were backing up into a heavy current and wind.

What do you think of the guys clogged spark arrester theory?

 

[mcleaves]

Re: Weird

MY guess is if water was flowing into the stern either from incoming current, reverse motion of the boat or both, that when the engine stalled it forced water back into the exhaust tubes and there is nothing really stopping it from entering the exhaust ports in the head. You may or may not have shutters but they don;t stop all the water.

Did it diesel before it died? If so it was running in reverse and acting like a pump sucking water in.

But the backing up when it stalled is the smoking gun IMO

 

[Fun Times]

Re: Weird

MY guess is if water was flowing into the stern either from incoming current, reverse motion of the boat or both, that when the engine stalled it forced water back into the exhaust tubes and there is nothing really stopping it from entering the exhaust ports in the head. You may or may not have shutters but they don;t stop all the water.

Did it diesel before it died? If so it was running in reverse and acting like a pump sucking water in.

But the backing up when it stalled is the smoking gun IMO

X 2, I was going to say the samething here.

 

[carolynrose]

Re: Weird

The water was running really hard and the wind was pushing about 20mph. When I put it in reverse and just started to give it gas there was a large gush of bubbles and it sounded weird just as it died. Then it wouldn't crank.

We jumped off to the walkway and pulled the boat into the slip.

Can it be that easy to suck water into the engine?

 

[mcleaves]

Re: Weird

One very common problem amongst go fast yahoos is they run at full sped and instead of coming to a stop by throttling down and idling for a minute before shutting it off, they throttle back hard and shut the key. Water hits the transom from the big wake that leave behind them and bingo, they are hyrdrolcked, just like you.

So yeah, it is that easy. In heavy chop I never shut her down. Gotta keep pressure coming out the exhaust. 99/100 times you probably won't have trouble, but as you saw that one time sucks..

Sounds like you were in an extreme situation and the engine died. That was the problem Once exhaust pressure was lost there was nothing keeping the water out. You may as well of had put a garden hoses in the exhaust.

it's not that you were going in reverse. Its that you stalled and were going in reverse and into a current on top oif it

 

[carolynrose]

Re: Weird

Thanks for the information.

I never back down hard when running I guess that's why I never experienced this before.

It all makes sense now. If I ever get in the same situation I'll definately take a different approach to the docking.

 

[mcleaves]

Re: Weird

What you were doing wasn't bad. I mean backing down is something you gotta do at times. The issue is that the engine stalled while you were. Same thing could have happened if you stalled and then a big wake came in behind you.

It's be good to know why it stalled..

 

[Showtime22]

Re: Weird

I hydro lock twice a year. Mostly when it stalls.
I would change the oil. You don't have to but I would. Your dipstick could not be showing the whole picture. Oil and water separate when it cools. When I have water in the oil it comes out of the oil pan plug first then the oil comes out after. If your engine is cold you could open the oil plug a little bit and see what comes out first. Clean oil or saltwater...

I usually use a trash bag to catch any fallout under the motor.

 

[Maclin]

Re: Weird

The clogged spark arrrestor could be one of the factors in why it stalled.

 

[EddiePetty]

Re: Weird

... I was docking in reverse when the motor stalled..... the spark arrester clogged completely clogged..

Curious here.........How do you 'completely cog' a spark arrester...on a boat??? Was it oil contaminated?

Ed in 'ol Virginny

 

[carolynrose]

Re: Weird

Just one of those stupid things that got overlooked. A Senior moment I guess. Anyway I cleaned it off and the rpms's came up. Probably was the factor in the stall.

I just don't understand how the boat ran so well with it clogged. The rest I get but where was the engine getting the air to run all the way to my rpm max?