2002 4.3L Mercruiser leaking water

[Bfett]

Hello,

I have a 2002 Four wins with the 190 HP 4.3L v6 merc. I started it up today after the long winter and it happily fired up and purred like a kitten. I opened the engine compartment and immediately saw water coming from the area of the bow end of the starboard side of the motor. The water is clear and only comes out when the motor is running. It comes out fast and appears to go straight down. I can not see the area clearly to find the leak and I'm not about to stick my hand down there while it's running.

I winterized the boat myself last year and made sure to get all five blue plugs out and completely drain it, but due to some potentially bad advice I did not put anti freeze in. I'm hoping since my engine is running nicely and the water is not milky that my block is not shot. Any thoughts?

Also, I can not find an online service manual without paying some questionable website money (never a good plan). I know there are PDF's out there if anyone has one and is willing to share.

Any and all advice is appreciated. I'm pretty bummed right now!

 

[Bt Doctur]

I winterized the boat myself last year and made sure to get all five blue plugs out and completely drain it

After taking the drain plug out you "probed the opening" to make sure it was open and drained?

 

[Bfett]

Sure did, I even ran it a touch and then checked the plugs a second time to insure no water was left.

 

[Bt Doctur]

see page 6A-14 in here http://www.boatfix.com/merc/Servmanl/18/18A6R2.PDF

 

[Scott06]

I think you forgot to put the blue plug back in the the bottom of the engine recirculation hose. It's there to drain out the hose. Alternatively there was some water in it and the hose is cracked. You probably have some form of the multi point drain in middle of linked page

https://www.google.com/search?q=mer...&hl=en-us&client=safari#imgrc=6GOKTGC6yofJEM:

Check these locations for plugs being put back in before getting bummed out.

If it's coming from the outside of the block and is not getting into your oil your a lucky sob as you can try JB weld over an exterior crack rather tha replacing the block. Good luck

 

[Bfett]

Ok, I looked at that page and see the drain plug referenced. The plug is blue on my engine and is installed. Am I missing something?

I should clarify that I have verified all five plugs are present in the engine.

 

[Bt Doctur]

If the manifold, engine block, and circ hose plugs are installed then there is no other reason for leakage except for a cracked block or missing core plug from freeze damage in that location

 

[Scott06]

Get a mirror and see if you can take some pictures of where the leak is coming from. Hard to diagnose without being there. Somethings leaking that shouldn't , but you already know that...

 

[Bfett]

I took a video of the area, but you can't see the source of the leak. It appears to be directly above and behind that engine mount. If I put my fingers up there i can feel a fairly large circular opening. I don't know if it is a jacket or a bracket or a manifold, but it's as cast so it's not a big blowhole . I think the water is coming from in there and then it dumps straight down over the engine mounting. Or should I say pours down. Very little if any water made it into the exhaust manifold because I pulled the plug to insure the O-ring was there and it was dry. That was the drain plug labeled "a" shown on page 6A-14.

As I type this, It seems extremely odd to me that zero water would make it to the exhaust manifold due to a cracked block. I'm running on muffs and a hose and 100% of the water it pumps in is pouring out of a crack in my block? really??? (water stops when engine off, even with hose remaining on). Wouldn't this water take the path of least resistance until it had enough pressure to spray through a crack?

I wish I had a good service manual because I could likely pinpoint the general location on a exploded view, or maybe there is a mystery hose in there that is not connected...

Somethings fishy and this is not a fishing boat...

Thanks for all the help everybody.

 

[Rick Stephens]

Core plug. Hopefully just rotted out or fell out. Have to jack the engine up a little and pull the motor mount all the way off to inspect and hopefully just replace.

 

[Bfett]

Rick Stephens, you are my hero. I may sleep tonight and might even get something accomplished at work tomorrow.

Is this something I should tackle, or just take her to the shop and get in line I'm very mechanically inclined, but know little about boat motors.

Thanks again to all!

 

[Rick Stephens]

Piece of cake.

Only difference on a marine engine is the core plugs need to be brass. Your V6 came off the GM assembly line just like any other truck motor. Working on it is just like on a pickup, some parts are marine to either withstand plain water cooling, which would rust out a regular water pump or core plug, unlike antifreeze. Or to keep from blowing up since unlike a pickup your motor is mounted in a bucket that doesn't allow heavier than air gas fumes to escape down, instead they collect in the bilge.

Point is, the motor is just like a pickup motor in how it gets worked on with just minor differences in components. You can rig up a lift, depending on boat design maybe even a couple 2x4s, to support the motor, pull that motor mount off, inspect and install a new core plug. Brass plug, use sealant on the plug. Reassemble and test. Cost you some time and maybe have to purchase a driver. If you take it in going to cost several hundred.

Rick

 

[Bt Doctur]

And that remove themselves by rotting away (steel) or pushed out by improper winterizing. They dont just fall out

 

[Bfett]

I agree Bt Doctur. Unfortunately It didn't just fall out. I can't figure it out because the stupid core plug is inches away from the block plug that I know I pulled and drained. Next year I will drain, pump antifreeze, then redrain (assuming I still have a functional boat). Also, thanks for the initial advice. You had pointed me right at the problem, but I was too thick to realize that a core plug is not a drain plug. I really should have known better....

I picked up some core plugs and a rubber plug at the parts store today. I guess the core plugs are crap because they are steel. I would much rather be pounding in a brass plug anyway....

Hopefully I can get the rubber plug in without lifting the motor as I really want to run it a bit on the muffs and make certain that my block isn't cracked before investing a weekend into repairing it. Anyone know if this impossible

All advice is appreciated (as are links to a PDF service manual)!

Thanks!
Brian

 

[Bt Doctur]

http://www.boatfix.com/merc/Servmanl/18/18A3R2.PDF

 

[Bt Doctur]

http://www.4shared.com/document/kIQrso3H/Mercruiser_Service_Manual_18_G.html

 

[Bfett]

Update - I dug in the bilge tonight and found not one but two plugs. Obviously I've botched the winterization.... Good news is that the oil is not a milkshake and the block is very clean with no visible cracks. The second plug blew out on the port aft, which is lucky as I have access.

The starboard plug is a nightmare and the only access is to pull the engine mount. I've pulled the two nuts and one bolt holding the engine to the mount and also the large nut and lock washer off the boat mount. This mount is still wedged between studs and if I try to lift the engine with the cherry picker it does not come off the mount. I'm guessing it's quite securely attached at the rear....

So how do I get this mount off? Do I need to pull the lag bolts that are holding the mount point to the transom? That doesn't appear to be a serviceable piece, but it appears to be the only way to pull the mount leg....

 

[Bfett]

I used to have skin on my knuckles, but I managed to get the lag bolts out. There is no movement at this joint.

How rigged is the rear motor mount? Is there any play or is the lift just fighting the mounts?


The only other think I see that might be holding it in is a bracket that appears to be attached to the fuel separator. It's hard to see what all that bracket attached to.....

Either way, the mount must be glued to the transom or something because it should at least rotate now, right?

 

[Rick Stephens]

SHould be three 3/8s bolts holding the triangular shaped upper half of the mount to the engine. With the lag bolts out, and those three bolts out of the block, the entire motor mount should just pull out. I would not have done anything with the big inner bolt and nuts.

 

[achris]

If you're lifting the engine and moving mounts, please pull the drive off first. And realign the engine before putting the drive back on. Or you may be back here asking how to replace the coupler.

My guess is you put the plugs back in after draining the engine. It wasn't completely drained and the trapped water froze. That's why you should leave the plugs out until spring.

Chris. ...