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Author Topic:   Water in Carburetors

Frank O posted 01-02-2009 07:09 PM ET (US)
Recently I had the 1994 Mercury 3.0L 225-HP 2-stroke carbureted 2-stroke tuned as part of annual maintenance. As noted in another thread, when we took the boat out last week it ran roughly, misfired and stalled.
Today I went back to the boat and it started promptly and seemed to idle well. I wanted to check the fuel-water separator filter, but couldn't get it loose by hand and didn't have an oil-filter-type wrench with me.
After letting it idle for a couple of minutes, I stopped the engine, tilted it up, and rinsed out the cooling system. After finishing this up, though, I noticed quite a bit of liquid draining out of the carburetors. This mostly came from the lower left-hand carburetor, but eventually some amount of liquid came out of the four lowest of the six carburetors. It added up to quite a bit of water -- it filled up a 5-cup Tupperware container, and more was dripping out even after that.
Right now I'm wondering the following:
1) Where is this much water coming from? Can the carburetors hold 5 cups of water and the engine will still run? Would this be water from the fuel, or is there any plausible path that cooling-system water could take to drain out through the carburetors?
2) Is it safe to let this be until I can get back to the boat in a week or so? Or do I need to worry about doing something promptly to avoid rust or corrosion?

Frank O posted 01-06-2009 11:22 PM ET (US)
Update ... my mechanic tells me there's no way for water to migrate from the engine's cooling system to the carburetors, so if there's water in the carburetors it has to be coming from the fuel supply. Guess I'll get the fuel-water separator filter off and work on getting any water out of the gas tank and line -- and maybe run the engine for a while off clean gas from a portable tank.
Chuck Tribolet posted 01-07-2009 08:02 PM ET (US)
I'm surprised the carburetors can hold five cups of ANYTHING. The
float bowls are maybe four ounces each, probably more like
two ounces each tops. 6*4=24 oz = 3 cups. 6*2 = 12 oz = 1.5 cups.
But if you got water out, there's water in the tank.
If you know which side of the tank the pickup is on, jack
the other side of the trailer. Disconnect the line from the
tank to the filter at the filter, and pump (get a generic
electric fuel pump at the auto parts store and put some
little jumper cable clips on it -- you use it for a bunch of
stuff over time) until you just get gas. Decant the gas
back into the tank, replace the filter and fire it up.
Now go pour a good 12+ year old single malt and reflect on
how the water got in the tank. Let us know the answer.

Chuck

Tom W Clark posted 01-07-2009 08:11 PM ET (US)
I do not believe there is water in the fuel supply. I also have a hard time believing the carburetors could hold that much water. I suspect the water is coming from somewhere else.
If the water were coming from the fuel supply, why would it pour out the carburetors? If there was no water in the fuel, would five cups of gasoline pour out of the carburetors each time you tilt the motor?
Frank O posted 01-08-2009 01:11 AM ET (US)
Tom, you make points that occurred to me as well. But if the water isn't coming from the fuel, where could it be coming from? Is there any way that water could migrate from the cooling passageways into the carburetors?
Chuck, if I do find water in the fuel filter and/or the tank, I'll definitely be hoisting a Pellegrino while I sort out how it could have gotten in there.

Tohsgib posted 01-08-2009 12:21 PM ET (US)
Yes it probably can but I doubt it would have run at all with 5 cups of water in the block. Are you sure it was just not laying inside the cowling?
Frank O posted 01-08-2009 04:58 PM ET (US)
Just got a phone call from my mechanic, who went down to check out the boat. He said that the gas tank, fuel-water filter and fuel line are free of water. He did see, however, that the air box that clamps onto the carburetors was full of water.
His theory is that water got into the outboard through vent holes located in the upper aft end of the cowling. When the engine is in operating position these vents aren't an issue, but when it is tilted up he says it's a weak spot in the design where water can easily enter:
http://www.inkbox.net/whaler/parts/225-vents.jpg
It was unusually rainy here in the latter part of December after the boat was back in its slip, but I have a good Sunbrella mooring cover that fits over the outboard that should have prevented water from getting in. My mechanic's theory is that the water could have gotten in there when the boat was being detailed at the end of its annual maintenance at his shop. I lashed out a little and had the detail crew do an extra-thorough job restoring the gel coat, T-top struts, etc; the mechanic said the detailing guys in the process used "a major amount of water." When he looked at it today he drained the carburetors, dried the air box, and said the engine then ran great.
I think I'll make a point of paying extra attention to any water that gets in the vicinity of the engine. For example I'm inclined to flush the cooling system at least once with the cowling off to make sure there isn't a leak somewhere inside. The water pressure is looking good when the engine's running, though.
Frank O posted 01-08-2009 05:07 PM ET (US)
Tohsgib, to your point, I still don't really understand where the water was pooling. I don't think it was just sitting in the lower cowling, because this appeared dry to me when I had the upper cowling off several times. My mechanic's impression seems to be that the water pooled in the air box clamped on the carburetors. When I observed water dripping out of the engine a few days ago, though, I removed the top cowling and the air box, and the water distinctly appeared to be running or dripping out of the carbs. If water pooled in the air box and the engine was later tilted down to run, perhaps it's possible that it then went into the carburetors. I sure don't understand how the engine would have run, even roughly, with that much water in the carburetors.
Tohsgib posted 01-09-2009 12:20 AM ET (US)
Neither do I....good job on the ??? hell I had too much beer tonight.

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Author	Topic: Water in Carburetors
Frank O	posted 01-02-2009 07:09 PM ET (US) Recently I had the 1994 Mercury 3.0L 225-HP 2-stroke carbureted 2-stroke tuned as part of annual maintenance. As noted in another thread, when we took the boat out last week it ran roughly, misfired and stalled. Today I went back to the boat and it started promptly and seemed to idle well. I wanted to check the fuel-water separator filter, but couldn't get it loose by hand and didn't have an oil-filter-type wrench with me. After letting it idle for a couple of minutes, I stopped the engine, tilted it up, and rinsed out the cooling system. After finishing this up, though, I noticed quite a bit of liquid draining out of the carburetors. This mostly came from the lower left-hand carburetor, but eventually some amount of liquid came out of the four lowest of the six carburetors. It added up to quite a bit of water -- it filled up a 5-cup Tupperware container, and more was dripping out even after that. Right now I'm wondering the following: 1) Where is this much water coming from? Can the carburetors hold 5 cups of water and the engine will still run? Would this be water from the fuel, or is there any plausible path that cooling-system water could take to drain out through the carburetors? 2) Is it safe to let this be until I can get back to the boat in a week or so? Or do I need to worry about doing something promptly to avoid rust or corrosion?
Frank O	posted 01-06-2009 11:22 PM ET (US) Update ... my mechanic tells me there's no way for water to migrate from the engine's cooling system to the carburetors, so if there's water in the carburetors it has to be coming from the fuel supply. Guess I'll get the fuel-water separator filter off and work on getting any water out of the gas tank and line -- and maybe run the engine for a while off clean gas from a portable tank.
Chuck Tribolet	posted 01-07-2009 08:02 PM ET (US) I'm surprised the carburetors can hold five cups of ANYTHING. The float bowls are maybe four ounces each, probably more like two ounces each tops. 64=24 oz = 3 cups. 62 = 12 oz = 1.5 cups. But if you got water out, there's water in the tank. If you know which side of the tank the pickup is on, jack the other side of the trailer. Disconnect the line from the tank to the filter at the filter, and pump (get a generic electric fuel pump at the auto parts store and put some little jumper cable clips on it -- you use it for a bunch of stuff over time) until you just get gas. Decant the gas back into the tank, replace the filter and fire it up. Now go pour a good 12+ year old single malt and reflect on how the water got in the tank. Let us know the answer. Chuck
Tom W Clark	posted 01-07-2009 08:11 PM ET (US) I do not believe there is water in the fuel supply. I also have a hard time believing the carburetors could hold that much water. I suspect the water is coming from somewhere else. If the water were coming from the fuel supply, why would it pour out the carburetors? If there was no water in the fuel, would five cups of gasoline pour out of the carburetors each time you tilt the motor?
Frank O	posted 01-08-2009 01:11 AM ET (US) Tom, you make points that occurred to me as well. But if the water isn't coming from the fuel, where could it be coming from? Is there any way that water could migrate from the cooling passageways into the carburetors? Chuck, if I do find water in the fuel filter and/or the tank, I'll definitely be hoisting a Pellegrino while I sort out how it could have gotten in there.
Tohsgib	posted 01-08-2009 12:21 PM ET (US) Yes it probably can but I doubt it would have run at all with 5 cups of water in the block. Are you sure it was just not laying inside the cowling?
Frank O	posted 01-08-2009 04:58 PM ET (US) Just got a phone call from my mechanic, who went down to check out the boat. He said that the gas tank, fuel-water filter and fuel line are free of water. He did see, however, that the air box that clamps onto the carburetors was full of water. His theory is that water got into the outboard through vent holes located in the upper aft end of the cowling. When the engine is in operating position these vents aren't an issue, but when it is tilted up he says it's a weak spot in the design where water can easily enter: http://www.inkbox.net/whaler/parts/225-vents.jpg It was unusually rainy here in the latter part of December after the boat was back in its slip, but I have a good Sunbrella mooring cover that fits over the outboard that should have prevented water from getting in. My mechanic's theory is that the water could have gotten in there when the boat was being detailed at the end of its annual maintenance at his shop. I lashed out a little and had the detail crew do an extra-thorough job restoring the gel coat, T-top struts, etc; the mechanic said the detailing guys in the process used "a major amount of water." When he looked at it today he drained the carburetors, dried the air box, and said the engine then ran great. I think I'll make a point of paying extra attention to any water that gets in the vicinity of the engine. For example I'm inclined to flush the cooling system at least once with the cowling off to make sure there isn't a leak somewhere inside. The water pressure is looking good when the engine's running, though.
Frank O	posted 01-08-2009 05:07 PM ET (US) Tohsgib, to your point, I still don't really understand where the water was pooling. I don't think it was just sitting in the lower cowling, because this appeared dry to me when I had the upper cowling off several times. My mechanic's impression seems to be that the water pooled in the air box clamped on the carburetors. When I observed water dripping out of the engine a few days ago, though, I removed the top cowling and the air box, and the water distinctly appeared to be running or dripping out of the carbs. If water pooled in the air box and the engine was later tilted down to run, perhaps it's possible that it then went into the carburetors. I sure don't understand how the engine would have run, even roughly, with that much water in the carburetors.
Tohsgib	posted 01-09-2009 12:20 AM ET (US) Neither do I....good job on the ??? hell I had too much beer tonight.