Water in carb?

[oden]

I've been having trouble with my 60hp mercury idling. It will idle shortly after I throttle down but within a minute or less it will sputter and die. I took a look at the carbs after my last time out and it appears to have water miView attachment 106830xed with oil in the bottom 2 carbs. Could this be bad reed valves? I have cleaned all 3 carbs replaced primer bulb, fuel filter and the plugs.View attachment 106830

 

[Texasmark]

Re: Water in carb?

Reed valves have nothing to do with water. They sit behind the carb and act as a one way switch allowing fuel/air into the crank and combustion chamber and close if any back pressure attempts to come back through the carb.

I would imagine that the filter screen in the fuel filter is small enough that water molecules can't pass through it so contaminated fuel is not the problem as I see it.

Check your combustion chambers for any signs of water/milky goo and get back. You could have a hole in a cylinder or leaking exhaust manifold.

Mark

 

[oden]

Re: Water in carb?

Thanks for the reply.I did take the plugs out of the bottom 2 cylinders and did not see any milky looking residue. I was trying to adjust the idle on the water, and when I took the cowling off the area around the power head had water standing around it. With it running in the yard on the hose I didn't see any water leaking anywhere. I had a oil leak about a week ago and I'm sure there was some oil left around the power head I couldn't get to. Could that be picked up with the water and sucked into the carbs? If so where is the water coming from? The seal around the cowling looks good, the grommet where the cables enter the motor doesn't fit well. I wouldn't think that much water would get in there, but IDK.

 

[Texasmark]

Re: Water in carb?

The engine is an air pump basically and to pump air out the exhaust it has to get it into the carb. For resistance to "seas", rain and other things, and for soundproofing, the air intake is "hidden", but it's there somewhere. On my engine, the inlets are at the top rear of the cowl, and unless you knew what you were looking for you wouldn't know they were there. It then goes through passages down both sides of the cowl and exits at the bottom of the top cover/cowling. In addition, my engine has a plastic "tuned" cover over the carb intakes designed to quiet the engine. Sucking water from inside the engine on mine would be extremely difficult, but if you took a wave from the stern, who knows where it would wind up.

HTH,

Mark

 

[oden]

Re: Water in carb?

Where do you think the milky water and oil in the carb came from? I'm just guessing at this point. I thought if the reeds were leaking it might cause a suction on the exhaust pulling in water.

 

[Maxz695]

Re: Water in carb?

That would mean water intrusion may be occuring through the lower retainer seals O rings or through a corroded exhaust port Baffle plate. Only then would water exit the carb through a bad (Bent or broken) reed valve. I suggest further testing before assuming this is your problem

 

[Chris1956]

Re: Water in carb?

Water separators do not filter out water. Water is heavier that gasoline and oil so it settles via gravity to the bottom of the canister. Fuel is drawn off the top of the separator, leaving the water at the bottom. If they fill with water, water will go right to the motor.

I recommend you siphon some fuel from the bottom of your tank (let the boat tank rest for an hours or so to let the water settle). Pour it onto a clear container and see if there is any water seperation. if so, our off the good fuel, and dump the water.

As was said, water can get into the crankcase from the cooling system, but it would be real unusual for it to get into the carbs or carb throats.

 

[Faztbullet]

Re: Water in carb?

Check your oil tank for water as I have seen bad caps let rain water seep thru into tank. The water under cowling can come thru the underside the cowling from water being deflected upwards from the lower unit(bad about this on toons)

 

[BigTroutMike]

Re: Water in carb?

Check your oil tank for water as I have seen bad caps let rain water seep thru into tank. The water under cowling can come thru the underside the cowling from water being deflected upwards from the lower unit(bad about this on toons)

I have a 1996 40HP Mercury with an oil reservoir that automatically mixes the oil from the res. into the gasoline as the motor runs. When I began having problems keeping the motor running, I eventually found that there was water in my oil reservoir. Because the reservoir sits vertically, the water would settle to the bottom and as the motor ran the water would be delivered to the engine (as the oil was supposed to) and eventually fill the bowls and stop the motor from running. So I had water and gasoline, and no oil. Now the reservoir is gone and I mix the oil and gas. A hassle? Yes. But peace of mind....