Still have a dang leak.....or a new one

[rickasbury]

OK team, you all walked me through pulling my 350 motor out of my 270 rinker, rebuilding my transom asy and back in the boat which was 100% sucessful for some time but back to leaking...

I did find that my shift boot cable had a tare in it, although I had replaced it so not sure what was up with that and thought my simple solution ( was able to replace it without pulling the out drive ) but still a leak. I tried to get a scope back in there but it's just to tight to get any useful views. I can see from the top of the motor I'm not leaking around the transom, steering pin, gimbal bearing...I'm feeling all my hoses and can't feel anything there either....I re sealed my trim manifold....I put all kinds of sealant on the transom ring when I put it back on and it is all squished out around the edges ( a mess I need to clean up ) and can't imagine anything is getting around that.

I tried the filling the bilge with water...zip.....

It leaks while sitting in the water with the motor not running so I assume it has to be something from at the raw water pump back. I have 4 thru hulls, nothing leaking there. It's a pretty good leak. My 350 is closed cooled, I have water from both the foot and a thru hull going to the raw water pump. So I have to get a better look at those hoses but one area I can't get to that absolutely keeps me up at night is the Y pipe not sealed properely on the transom asy. How can I check that? My exhaust bellows is off....I was thinking I could shove a hose in their and stuff some rags around it to get a somewhat seal on it and crank up the pressure, but since it also is the exhaust, assume water is going to go into bad places? I guess I can take the elbows off from the motor and somehow block them off so that water does not get to the motor.....I was concerned when I put the Y pipe on the bolt tourque was only 24 lbs and I don't recall it being any special fastners, I did put new ones on and anything that merc said to be there is there....

 

[Rick Stephens]

You might be able to get your phone down under the motor to video the Y pipe. That's how I found the leak on mine. I had to pull my just installed motor out because I pinched that o-ring gasket. Leaked pretty good. Get one of those phone tripod clamps and attach it to a stick.

 

[76SeaRay]

Harbor Freight has an inexpensive inspection camera with a long flexible reach on it

 

[rickasbury]

Well, aside of those helpful facts, how can I test it on the trailer? The problem will be even if I can get a camera down there, once there is water in the bilge you won't be able to see where it'c coming from...I think I will will the boots off the elbows and see if I can get a little water pressure going and see if it leaks into the bilge. I also wonder if A, can I get to those four nuts to tightne and B, if not, can I pull the motor forward enought to get to them without pulling it out of the boat? I have about 8" or so I can rig a hoist to it and swing it forward....if that is not the problem I will put it back in the water when weather allows and get a scope I can explore with...

 

[Bondo]

My exhaust bellows is off.
I think I will will the boots off the elbows and see if I can get a little water pressure going and see if it leaks into the bilge.

Ayuh,..... Duct tape the exhaust port, outside the transom, 'n just fill the y-pipe with water from the top, inside the boat,....

'n in my experiences, the motor has to come out to reach the y-pipe bolts,.....

 

[achris]

Pull the drive, pull the engine, reinstall the drive. Take the boat to a local ramp and reverse it into the water. Climb in the boat and find the leak. If it is the y-pipe O ring, engine had to come out anyway.

Chris.....

 

[rickasbury]

you guys are a real buzz kill......

 

[Bondo]

you guys are a real buzz kill......

Ayuh,...... Would you rather that we lie to ya,..??..??

 

[Rick Stephens]

you guys are a real buzz kill......

sounds like you should just go boating

 

[achris]

you guys are a real buzz kill......

Nah, that's what life is...

 

[rickasbury]

ok, so here is the plan for the weekend. After a little thought....so I filled the bilge with water so if the y pipe was easily leaking, i would have seen water...so I think I'm back to putting a little pressure to it...I will pull the rubber elbows off, cover with some plastic and put the clamps back on...did this when I was testing to the boat for leaks to begin with on my saga with the motor out. I will also put the muffs on the foot and crank up the pressure so that should pressurize the raw water hoses up to the water pump. I'm thinking the boat in the water would put a lot of pressure on both these systems I may have not been able to duplicate by just putting water in the bilge...this is I can do without pulling the motor. The manual said on the bolts for the y pipe is only 24 ft lbs which sounded really lite to me and I'm concerned they did back off with vibration perhaps... we will see. I'd bet I can move the motor forward enough to get at the four bolts if it is lose- there is a new seal there already.

 

[nola mike]

How about blocking exhaust and filling y pipe with acetone?

 

[Rick Stephens]

Can't put pressure on anything with muffs except the bottom side of the impeller. Water doesn't pass through the impeller without it be turning.

 

[achris]

...I will pull the rubber elbows off, cover with some plastic and put the clamps back on....I will also put the muffs on the foot and crank up the pressure so that should pressurize the raw water hoses up to the water pump. .

Oh, such a bad idea!

First off, water shouldn't go passed the impeller. Second, if it did and filled the engine with water, that water normally runs out the exhaust. You just covered it's exit. Where do you think the water will go if it's at the exhaust elbow and can't go down the pipe? Straight into the exhaust manifold! Any cylinder with an open valve is in for a soaking...

Rethink.... Are you trying to pressure test the engine? If so you need to remove the elbows and block the water from passing from the manifold to the elbow... Don't ever block the water's path out through the pipe. Quickest way to hydrolocking an engine....

Chris....

 

[rickasbury]

So achris I'm trying to test two things...I want to test the y pipe seal and I want to test the raw water hoses from the out drive up to the water pump.

For the y pipe I would pull the rubber elbows of, block off the tops with plastic. The exhaust bellows is off so I can take a hose with a rag around it and insert into the exhaust building up a little pressure and see if the y pipe is leaking at the seal.

I'm closed coolin so if I put the muffs on the out drive and turn on the water like I'm going to run the motor, I'm testing the hose from the out drive to the strainer...anything that would get by the impelleim can't get to the motor right?

 

[tank1949]

You might be able to get your phone down under the motor to video the Y pipe. That's how I found the leak on mine. I had to pull my just installed motor out because I pinched that o-ring gasket. Leaked pretty good. Get one of those phone tripod clamps and attach it to a stick.

The first thing I did after rebuilding transom and installing transom assemblies AND new Y Pipes, was to fill bilge with water above and over Y Pipe and monitor for leaks. He may also have leak in P trim manifold at bottom of gimbal housing? No leaks! A warm fuzzy feeling... I suspect transom rot. He may be able to plug gimbal/OD exhaust and fill Y-pipe from top after removing one exhaust bellows? Regardless... if leak anywhere in Y pope or gimbal housing means pull motor. Been there!

 

[Rick Stephens]

I'm closed coolin so if I put the muffs on the out drive and turn on the water like I'm going to run the motor, I'm testing the hose from the out drive to the strainer...anything that would get by the impelleim can't get to the motor right?

We are both trying to tell you that you cannot pressurize your water lines between impeller and exchanger this way. The impeller has to be trash if water goes by it. And if water were to get by into the cooling system it ends up in the exhaust and back into the heads. There is no way to pressurize the other side of the impeller coming FROM below the impeller.

The correct way to test the inline is to pressurize from the water in line at the exchanger. This will put pressure on the in line all the back to the impeller. I sure as little green pepper wouldn't put more than 20 pounds or so. That part of your cooling system is designed to be run OPEN, as in nearly no pressure at all.

 

[rickasbury]

Ok, I'm not saying this right. I'm not trying to test anything from the raw water pump forward. I'm looking at the hose that connects at the transom where water is pumped from the foot and goes to the sea strainer which would normally have only suction on it drawing water to the raw water pump. I also have a thru hull and a second hose for that. Both hoses connect to a y at the sea strainer and then one hose on the exit to the strainer goes to the raw water pump. The boat is not in the water so I'm trying to see that if I put the muffs on the out drive like I'm going to start the motor, if any of those hoses are leaking.

For the y pipe, it would be completely disconnected from the motor and would put minimal water pressure to it to see if the seal where it mounts to the transom is leaking.

 

[achris]

So, let's distill the information we need.

Engine is a 350 V8 MPI, with closed cooling, a Bravo III drive, and an engine mounted raw water pump. You have both drive intakes and a thru-hull intake, which go to a strainer before the engine mounted raw water pump.... Got it!

You're getting sea water in the bilge, not engine coolant.

You're trying to 'pressure test' the line(s) from the drive pick ups, to the suction side of the raw water pump... BTW, putting the muffs on your foot will only make your shoe wet, don't do that.

Ok, filling the y-pipe with water... Yeah, that might work...

Have you checked the hull for any cracks that may be the source of the water? You say it leaks even when the engine isn't running.... When I first put my 4.3LX in (1994) I also had water getting in the bilge. I even pulled the engine and transom assembly off and completely sealed it all again. Still had water coming in. Then my fibreglass guy asks if I've checked the hull. Sure enough, a rotten stringer, and a small crack, enough to account for the water I was seeing. He fixed it all up for me and the only water I get in the boat now is stuff I bring over the side when I come back from a dive.

Chris......

 

[Rick Stephens]

We got it. No water will go into those lines from putting muffs on the leg water inlets.

Also, never think about sea water pumps sucking - they don't. They have zero suction capability and must be primed by either a water supply under pressure or being underwater. The pumps themselves have vent holes in them to allow air to escape and water to enter the pump body. Because of the vents, it is impossible for them to produce suction.