3.0 alpha one water leak only when running

[Rmcduffie49]

Need some advice. Have a 2002 stingray 180 ls with the merc 3.0 alpha one. I am no stranger to the bellows job and have even pulled a 5.0 merc out of a bayliner. With that being said I'm stumped on a water leak I am having with this boat. There is no leak unless the boat is running, and when it is running it is leaking somewhere under the driveshaft but above the j pipe. Could possible be the top of the j pipe really can't see it. But there is a steady line of water that runs down the side of the j pipe into the bilge. Again only when the boat is running, doesn't seem to increase with revs, turning side to side, or trim. My thoughts are maybe the top of the j pipe is corroded? The j pipe I can see and feel however seem to be in real good shape so I have my doubts on that. Any ideas?

 

[Scott Danforth]

Could be the flapper dropped down and the pin wire thru the exhaust pipe.

Could be freeze damage and you have a crack in either the block, head, or manifold/riser.

My first idea is to follow that stream of water to the source, then start pulling things appear and inspecting

 

[Rmcduffie49]

Just walked back up from the dock, it appears the stream originates at the top of the j pipe near the top bolt. I'm unfamiliar with the removal of the j pipe, so I'm guessing but it's either a cracked ear at the bolt or maybe a gasket for the end of that pipe? I think I'm safe as far as the block because it's originating right near the j pipe connection at the transom.

 

[Rmcduffie49]

Would the exhaust elbow tube only leak when the motor is running or all the time?

 

[alldodge]

I'm thinking you have crack in the exhaust elbow
http://www.mercruiserparts.com/bam/subassembly/30905/4893/270

Other thing could be a bad exhaust boot

 

[Rmcduffie49]

All dodge I am thinking that too and it looks like where the water is coming from. However what doesn't make sense to me is why it would only leak there while running. Does that elbow not sit below the water line and have water in it even with the boat off?

 

[alldodge]

Part of it is under water, the rest is not. Only other thing in that area is the water hose coming from the drive. Only reason I didn't mention it is you said its coming from under the drive shaft. The hose should be higher. Now if the hose has a pin hole it might be spraying water over

 

[Rmcduffie49]

Would the water hose only leak when the motor is running? It's just so dang right back there I can't be positive. All does look dry above the driveshaft though.

 

[Rmcduffie49]

Is there a link to a good diagram or picture where I can see where everything is on the backside of the transom plate

 

[alldodge]

Yes, when the motor starts the drive impeller pumps water through the hose under pressure. I'm sure its hard to find, moving your hand around a running motor is hazardous.

 

[alldodge]

Image

 

[Rmcduffie49]

Thanks dodge you have been very helpful, pulling it out of the water tonight and I guess beginning the fun. I dread it lol! If I do have to pull 3.0 motor because it ends up being exhaust tube would you recommend using front stringer mount bolts or the upper middle engine mount bolt?

 

[alldodge]

If your asking where to put bolts in for using a chain to lift the motor, my first thought is your motor should have a couple factory lifting rings/brackets on the motor. Haven't done a 3.0 in a long time, but one should be on the thermostat housing or real close by. The other should be on the rear of the motor.

 

[alldodge]

Here found this in the install manual. Says don't use the thermostat housing, use the one to the side in front and the opposite side in the rear. One on housing is used to adjust front mount install. Use just "b" points

 

[Bt Doctur]

pull the drive, almost positive you`ll find water. and because the rubber ring is missing or dislidged and the water inlet O ring is missing or dislodged
In the picture from alldodge where the driveshaft comes thru are 2 vent holes one at 12:00 and one at 6:00

 

[Bt Doctur]

 

[Bt Doctur]

 

[Rmcduffie49]

Are there supposed to be o ring gaskets in each of the vent locations?

 

[Bt Doctur]

No, just that big square rubber ring glued inplace
see post 4 in here http://forums.iboats.com/forum/engi...-outdrives/10194721-alpha-one-gasket-question

 

[s.hadley81]

Just a suggestion but maybe a camera phone can give you a better look where your head dont fit so you can get a better look at the leak.