Almost Sank. Water in two stroke tanks. Merc 150 2005. Need some direction.

brew0688

Cadet
Joined
May 18, 2010
Messages
13
2005 Proline 21ft Sport
2005 Mercury 150 two stroker. 500 +/- hours since new.

Memorial Day weekend me and a couple friends take the boat out to go dive one of the local reefs. We are 9 miles out. I come up from my second dive, and notice the boat isn't quite sitting right in the water. I open the hatch to the hull, and find that it is completely full of water (level with the deck). I open the rear seating area hatches that cover each battery and my electronics, and both batteries are submerged. Each time I turn on my bilge, it shorts out and turns off. I decide that I am taking a risk by starting my motor at this point, but it's that, or turn it and my boat into an additional part of the reef, so I crank her up. She starts right up.

My buddy takes the helm and we start driving back to land, as I start trying to figure out where this water is coming from. I know for certain that the plug is in place. I call the coast guard to have someone pump me out, but they're "an hour away" and tell me to put my life jacket on.

At this point, the motor is running well, but sounds bogged down, which I attribute to the massive amount of weight it is pushing. Using a bucket I manage to get a reasonable amount of the water out of the boat, and realize that one of my batteries had come free, and broken the pvc scupper that drains my deck splash out through the hull. This has resulted in water entering directly into my hull from the outward going end of this drain. I put a plastic bag in there and make sure its closed.

Long story short, I make it home, but the motor cut out several times. By the time I'm back at the dock, the motor has a strange new "tick" to it that I'm not used to hearing, and cuts out frequently.

I immediately take the boat to the shop and completely rinse out the hull with very very soapy water and rinse it with fresh. Over the next few days I clean out the hull, remove my bilge pump, and try to establish what damage has been done.

I pump out about 5 gallons of gas. The first gallon has a very small amount of water in it. I replaced my fuel / water separator. I also drain my carbs.

Two stroke res. is mounted below deck, and as far as I can tell at this point, it is full of beautiful blue/green two stroke. I open the cap of the motor mounted secondary tank, and it looks the same. Clean as can be. I change my spark plugs, and replace both thermostats, and decide to see if she'll run. (See video)

youtube link (swear its safe): https://youtu.be/s5LJI5bHKxc

After I ran the motor this way for a few minutes, I'm doing some more inspection around the motor, and notice a separation of color in the small two stroke tank on the motor. I drain it, and find that it has a decent amount of water in it. Of course, the motor has been pulling purely water into the crank, as the two stroke floats perfectly on the top of it, and doesn't mix at all. I remove the main two stroke tank to find that it is about 50% full of water after all. I completely drain every line that has anything to do with two stroke delivery and flush it out with fresh oil. Removed the tank on the motor, clean it out, replace it, and fill it with new oil.

At best I can hope that the slushing around of the oil / water in my two stroke tank injected a portion of oil into the motor with the water it was pulling, but I can't be sure.

I opened up the fuel line right before the delivery point to the fuel pump and injected probably 50cc of two stroke oil, and reconnect. I crank the motor up and it starts and runs. I expect plumes of smoke to be coming out of the exhaust, but nothing.

The motor appears to be running decently, but as I said it has a new "tick" to it. It does run as though it has somewhat of a timing issue. I'm

I need some advice as far as where I should go from here. I'm uncomfortable with the fact that I'm not smoking, especially with how much two stroke I have been injecting into the fuel lines.

Thanks in advance for any help.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,550
This is not the first time this sort of thing has happened.-------Start with a compression test.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,126
Mercs of that size normally have a motor mounted oil reservoir as well as a hull mounted reservoir. Make sure all are water free. You can let the water settle and siphon it out of the tank. Pull the injection hose to the pump and bleed that of water as well.

Hopefully no damage was done to your motor.
 

brew0688

Cadet
Joined
May 18, 2010
Messages
13
So I went ahead and did a compression test. All three cylinders on port side are 90-95. Other 3 are between 100-110.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,550
I would pull the head on the low cylinders to inspect the cylinder walls.
 

brew0688

Cadet
Joined
May 18, 2010
Messages
13
I would pull the head on the low cylinders to inspect the cylinder walls.

Pulled the heads. 3 of the sleeves are pretty severely scored.

Guess I'll be starting my hunt for a replacement powerhead and sending this block off.
 
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