HELP Water in carburetor!

[SailingReckless]

Just took off my carburetor to take it in to have someone look at it and it was full of water! I know the fuel supply from the mechanical fuel pump is good clean fuel. Does that mean that the water is entering from the manifold? When I put the boat in the water this year I got it to runSo i suppose obviously I have water intrusion. Can anybody walk me through how to run it down and find out where its coming from? I did earlier post of video of the exhaust smoking and was advised that it was steam from water getting in somewhere it shouldn't be!

[Antibes]

Post from 2007.

http://www.moyermarineforum.com/forums/showthread.php?t=1319

[ndutton]

I know the fuel supply from the mechanical fuel pump is good clean fuel.

HOW do you know?

[Dave Neptune]

If indeed the fuel being supplied is free of water then the first test is to pressure check the manifold. It can be done in place. Many links on this site for testing instructions.

Dave Neptune

[SailingReckless]

I disconnected the fuel line from the carburetor and manually pumped out fuel into a jar and it was clean.

[ndutton]

I disconnected the fuel line from the carburetor and manually pumped out fuel into a jar and it was clean.

I had to ask. You'd be surprised how many times someone says, "I know such and such is good" only to find several tests and days later it wasn't.

I'm looking forward to the results of your manifold pressure test.

[joe_db]

One way this can happen is a poorly designed or defective exhaust flooding the engine.

[Dave Neptune]

Reckless, you say the carb was full of water, can you give a bit of a description please. Was it in the bowl and if so how full of water? Or was it just water in the throat of the carb? Or did the carb just "show" water damage?

If you were out on the water and the boat was ah rockin the pump could suck some water off the bottom intermittently and still show a "clear of water" check when sitting still. It can happen so diagnosing one thing at a time is NECESSARY.

Check the manifold, if good THEN check the exhaust for syphoning back to the manifold. If water is "syphoning back" you should also see a "rise" in oil level or milky looking oil. If the oil level has risen the water can be sucked off the bottom before mixing with the oil for easier flushing. If no milky oil do look to a serious pressure check of the manifold.

Dave Neptune

[capnward]

For checking the manifold, I've heard of two ways. One is to get a fitting for a Schrader valve like on tires, and a bicycle pump with a pressure gauge. Close off the other end of the manifold. Pressurize the manifold to (I believe) 20 psi, and if it holds that pressure for a long time you're ok. The other way is to blow through a hose in one end while the other end is closed. In the descriptive words of Ken at Moyer, make "your eyes bulge out" with your lung pressure, and listen for air escaping, and feel if the pressure lessens. That's what I did recently, and it felt solid, so I moved on. If the manifold is good and the oil is not milky, water may be siphoning back from the exhaust. This can happen with some exhaust systems when you crank the starter for a long time without the engine firing, and with the raw water not turned off. Was it running ok before you removed the carb? Is there water on the plugs? If the water was only in the choke area, you may be able to clean and reassemble the carb.
I recently had a milky oil problem, but compression was good, and manifold and block each held lung pressure, the engine ran, no water in the cylinders or carb, and my exhaust water jacket doesn't allow water back into the engine, so it turned out to be the shot seals and worn shaft on the water pump.

[edwardc]

Another possibility we've seen reported before is water from a deck leak dripping directly into the flame arrester.

[joe_db]

I had this issue with a poorly thought out exhaust system redesign. Until I fixed it, I had to keep the engine running at idle under sail to keep the water out. That actually was my diagnostic, went sailing on a rough day and kept the engine on = no water.