Hydro-Locked Lesson Learned

[Lundman]

Well up till about a six weeks ago I was un-familar with the term but now have quite a few $$ into learning the meaning of "Hydro-Locked" .

Here are the symptoms: First as you shut-off your boats I/O motor and it diesels and then (without hearing) it backfires before it dies... Then on the restart the motor won't turn over. You believe the starter is messed up so you head for the boat launch. You take out your starter and have it checked -- it fine. You try to turn the motor over again and it's frozen solid. Then you start pulling the spark plugs and on the last plug water comes poring out. You might think - blown head gasket, cracked head, cracked intake manifold, or cracked block. Wrong...!!!

When here's what happened ... The backfire has sucked water from the exhaust manifold into one or more cylinders - In my case on my V6 it sucked water into 3 cylinders - one on one side and two on the other side.

Since I was up in Oregon I wasn't going to let this event ruin my once a year salmon fishing trip - so I fished the remaining days with my kicker - not as good as having the main motor but luckily the wind and weather cooperated and we fished.

My fix turned out to be a total engine rebuild from water damage.

Here's what I should have done.....
1) First pull all my spark plugs and disconnected the coil.
2) Then turned over motor until all the water is purged from the cylinders.
3) Then re-insert the spark plugs and start the motor.
4) Run until your motor is running smoothly
5) Check oil drip stick see if water got into the oil and change oil if necessary.
6) Turn Down the idle screw setting until the motor barely runs and stops immediately when the key turns off.

Lesson learned and maybe this will help someone in the future. Luckily I have a friend with a machine shop and my costs were about 1/2 for a total rebuild because I rebuilt the motor myself minus the cost of gaskets, bearings, valves, pistons, rings, and machining.

I re-fire this weekend and hopefully will get in a couple trips before the hardwater hits.

BOAT = Break Out Another Thousand..... [:/]
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[Kent]

Wow Craig, sorry to hear you had that happen. Tough lesson to learn. I certainly wouldn't have known what to do and likely would have done the exact same thing that you did.
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[wiperhunter2]

Wow, that was a costly lessen to learn but what do you think caused it to happen in the first place? Has your motor ever done anything like that in the past, backfire I mean? Sorry to hear about the expensive lesson.
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[Lundman]

Another thing that I learned was when you take a boat from our elevation down to sea level (or in my case 400 ft. above sea level) the motors performance increases 23%.

So basically my motor was running like a champ. But the change in elevation also caused the motor to diesel when I shut it off. Around the local ponds it shutoff without any problems. So the idle was too high for the lower elevation and I should have slowed the idle down.

The strange thing was it's done this same routine every year for the past 8 trips to Oregon. This trip was no different expect for the last time.

Again Knowledge is power and I hope this will help some other poor sole avoid this costly learning adventure...
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[GEEZER]

Just my two cents worth. The dieseling problem could possibly be due to the octane of the gas you were using. If you had much gas that you bought here in your tank, it was probably one or two octane numbers lower than what you would get at the lower altitudes. Couple that with the possibility your spark timing is advanced some to compensate for the higher altitude and it can get kinda iffy. Whenever I take my old boat to a much lower (1,000 ft.) altitude than our area, I always leave some room for at least a 1/4 tank of premium to compensate at the start and then I always run mid grade while I'm there. So far so good doing that.

Sorry you had the trouble. If I had to rebuild the engine in my old boat, I'd have twice as much in the engine as the whole boat is worth.
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