Hydrolocked engine 5.7 0m643181

[golfwins]

A month or so ago, I took the boat out for a short ride. I killed the engine and dropped anchor for about 30 minutes. I don't recall if I stopped quickly, killed the engine causing water intrusion from the exhaust, but it's possible. I decided it was time to go back in and I tried to crank the boat and it would not crank. It did crank a couple of times and sounded really bad like clanking so I stopped.

I got towed in by a friend and I put it back in the slip for the night. I came back out the next day and pulled plugs. I had water in probably 3 of the cylinders on the port side. I got the water out and after some cranking, it started and sounded normal.

Yesterday, I decide to pull the boat to replace water shutters. I start the boat with no issues. This is an odd ramp so I power myself onto the trailer ask my buddy if we are good, then kill the engine.

I replace both shutters, even though both were still in place, but you could tell the rubber was delaminating from the metal part of the shutter. Still firmly in place though. I button everything up and go to put it back in the water and when I crank the engine I hear that horrible clanking sound I had heard a few weeks ago when this all started.

I pull the plugs and see some water come out of the port side again. Not near as much as last time, but it's enough. Anyway, I'm bringing it home after work today. I'll start by pulling all the plugs, trying to crank it and see if I hear that miserable sound. If not, I'll start with compression test and if that passes a leak down test next.

I think my boat has always been in freshwater, but I can't say for sure. It was originally near the Houston, TX area so could have been in salt. Let me know if you guys want to offer some better steps in troubleshooting. I also have an inspection camera if that helps.

Thanks,
Jeremy

[mmwjr]

Sounds like a good plan of attack. Have you checked for water in the oil or see if the level has increased?

[golfwins]

I didn't check the oil, but I'll check it when I bring it home. I had just changed the oil a few weeks ago so I didn't think to check the level after yesterday's issues. Thanks for the response.

[jparsons121]

+1 on Mikes suggestion to check the oil level to see if water got past the top end.

Water in the cylinders will only come from a few places.
Backflow up the exhaust is a possibility, but it’s also possible from leaky exhaust risers/manifolds or head gasket issues.
What cylinders did you get water in? &
What year is the engine?

[golfwins]

Thanks for asking that question. I had water in the front 3 cylinders in the port side. The cylinder closest to the back of the boat was perfectly dry. I feel like out of the 3 wet cylinders, the middle one was the by far the most wet. I can get more details in a bit. Going to grab a bite to eat. Compression was about 175 on the dry cylinder and I guess because the other 3 were wet, they were about 200. I didn't touch the other 4 cylinders since I feel the port side is the problem.

[golfwins]

Not sure if this helps troubleshoot, but I do have the dry joint risers.

[mmwjr]

With those compression numbers the head gasket is good. Having dry joint means it’s not a leak at that point allowing water in. Do you boat in salt water and if so how old is the exhaust? Could be an internal leak for corrosion.

[golfwins]

The last owner and myself only used the boat in freshwater. I'm not sure about the original owner. As far as I know the risers are original.

[mmwjr]

How are you shutting the engine down? Bring the boat to a slow stop and let it idle a minute then turn the key off? Does the hydro lock occur when running the engine on muffs?

[golfwins]

The first time it happened, I can't recall doing anything odd. I feel like I let it idle while I dropped the anchor.

The second time had to have happened while loading it on the trailer. I'm using a friends trailer on a ramp that is not ideal. So I had to drive it onto the trailer. Once my buddy said we were good, I turned the engine off.

I guess it could have happened while putting the boat back into the water. We were backing slowly because there is a drop off ok the side of this ramp and we were taking our time.

[golfwins]

I did check the oil last night, and I would say it's somewhere between an 1/16"-1/8th" higher on the dip stick.

The oil has less than an hour of run time on it. This pic shows a little bit of milkyness on the end of the dipstick.

[golfwins]

Here is a pic of the problem side of the engine.

[shrew]

1) Pull the plugs and let all the water drain from each cylinder
2) Replace the plugs and do an oil change, including the filter.
3) Run the engine until it comes fully to temp.
4) Shut it down and do another oil change
5) Repeat steps 2~4 at least 3 - 4 times.
6) When done, replace the spark plugs.

[golfwins]

Can I just use some inexpensive oil for these quick oil changes?

[mmwjr]

Originally Posted by golfwins

Can I just use some inexpensive oil for these quick oil changes?

Yes but use the correct weight.

[mmwjr]

Originally Posted by golfwins

Here is a pic of the problem side of the engine.

You need to disassemble the exhaust to look for signs of water intrusion.

[golfwins]

Thanks for the feedback guys. I've read in an other forum of a way to do a pressure type test to see if you can hear where a leak may be coming from. There weren't many details on the process. Have you guys heard of something like this? If so, do you h know the process. I think part of the process was blocking off some hoses at the thermostat and adding a schrader valve to one of the thermostat housing ports.

[golfwins]

Going to list the steps that happened yesterday.
1. Started boat fine in the slip and drove to the ramp.
2. Powered boat onto trailer and turned off engine.
3. Replaced both water shutters.
4. Backed boat back into the water (I feel like pretty slowly).
5. Boat will not start and is hydrolocked.
6. Pulled boat to house, pulled all plugs and boat now freely cranks with good compression.

I'm going to run it on water muffs after work and see if I get any water in the cylinders. My thought process is that if I don't, maybe it came through the exhaust during getting it on the trailer or putting it back in the water. Maybe it happened before I put the new water shutters in. I'll post pics of the old water shutters in a bit. They don't look bad in my opinion.

[golfwins]

Old water shutters.

[golfwins]

I was wrong, the oil was completley milky. I'm running it up to temp on the first oil change and filter now.