Logo

4.3 Mercruiser exhaust water coming in boat

whipsaw

New member
I have a 2005 Baja 192 Islander with a 4.3 Mercruiser. I did all my pre-season maintenance today and charged the battery. I fired it up with the garden hose adapter. Noticed no water coming out the exhaust. Instead it was coming out from under the engine. I can't see anything under there other than the water pouring out when it is running, but can't tell where it's coming from. A couple other forums mention a corroded exhaust pipe. Thoughts? If exhaust pipe, any idea how much that might cost to have repaired? Thanks in advance.

Jim
 
Since you are not getting any water out the stern I would be looking very closely at all hoses and check the engine core plugs carefully...........
 
Hey guys, thanks for the quick reply. Water was drained from the engine by opening all the blue cap drain plugs (5 total) and letting it run out. Cylinders and carb fogged. If it is a cracked block, I have read where others used JB Weld to seal it and it has worked fine. Thoughts on that? There are no signs of water in the oil.
 
Last edited:
Others may have a different opinion........But if it turns out to be a crack in the block, that is one big a$$ crack, I would not think a crack that size would be a candidate for any type of epoxy repair...
 
when you removed the plugs did you probe the openings?
is there a drain for the power steering cooler?
did you remove the lower hose from the cooler drain it?
di you remove the drive to drain the inlet hoses?
 
I did probe the openings. They all drained a considerable amount of water. I have done it every year. No drain for the power steering cooler I am aware of. Did not remove any hoses. I did squeeze them to help push water out. Not sure about the inlet hoses. If it was not one of those 5 then no.

You guys have a ball park cost on block replacement from a marina?
 
don't go replacing anything until you find the problem. remove the inlet hose from the therm housing, insert garden hose and see if hose or ps cooler leaks
next ,remove large hose from the housing ,inset hose see if block leaks
 
UntitledL_zps11ef1823.jpg
 
Last edited:
Thanks Bt. Going to try it this afternoon. I will let you know. I have a video I took with the cell phone. You can't tell much but if you think it will help, I will try to post it.
 
Got the message. Starting on it in a couple hours. Thanks again. I've included a link to 2 videos I got with the cell. Horizontal is the original and is turned 90 degrees right. I fixed it with the vertical video but you can't see quite as much. Hope they help.

 
If you ran the engine for any length of time while the water was leaking, you may have burned or blistered the interiors of the exhaust couplers, and possibly the back-flow prevention flappers.

Pull this all down and inspect prior to running it after the ultimate repair.
 
Probably ran no more than 2 minutes including before I noticed the issue and firing it up a few times to try and find the water leak. Those test times were no more than a few seconds a piece to keep the motor from getting hot. When I was reaching under to feel for the leak, nothing was hot to the touch (water, motor parts, etc). Will be sure to inspect those areas though. Thanks.
 
Bt, if I understood and did correctly the water leaked when running garden hose water through the lower (larger) hose. I attached a picture. I ran water through the top hose in the direction of the yellow arrow and it ran out the exhaust without leaking inside. I ran water through the bottom hose in the direction of the red arrow and it leaked inside the boat, just like when it's running.

Baja Leak.jpg
 
Chris, thanks for the follow up. Since the leak is in a place I can't get to I presume I would need a lift to get the engine out, or at least raise it enough to check the plug. I guess I am going to bite the bullet and take it to the repair shop.

All, any ideas what a core plug replacement cost might be? Eastern NC prices? I see the plugs themselves aren't very expensive. I'm sure the labor will be hefty. Any thoughts are helpful. I don't want to get taken to the cleaners. If I know roughly what to expect is going to be helpful.

Thanks all for the help and info by the way.
 
More of a question as to why it would be pushed out by freezing water. And the next question is did the block crack.

I would get a tree and a come-along hold the motor by the therm hosing,remove the motor mount, install a rubber plug first.
Test run it to make sure the block is not cracked
 
Last edited:
Put a 4x4 across the gunnels of the hull and use a ratchet strap. Take the lag bolts out of the base of the mount and lift the engine with the ratchet strap until the mount lifts off the hull Then remove the three bolts holding the mount too the block. Permatex the new core plug and drive it in. Look at another core plug on the block and you will see how far to knock it in. Shouldn't take more than two hours.

Hook up the hose and run it until hot. Maybe you dodged a bullet.
 
So basically just elevate the engine enough to pull the motor mount off, then check the plug or for a crack? Hopefully the plug is in fact missing versus a crack. Test with the rubber plug. If good, Permatex the new plug in same depth as others. Test run. Got it.

Other than disconnecting the battery, any other disconnects or removals need to be done prior to starting?

Bt, you said hold the motor by the Therm Housing. I am not sure I know where that is. Do you have a schematic on it by chance?

It will be a bit later in the week before I get the chance to try it. I'll keep an eye on the thread and follow up to let you know results for sure.
 
Finally got some time to work on the leak this past weekend. It was the core plug under the motor mount. I popped a new one in there test ran it on the hose and seems to be good to go. Thanks everyone for the help.
 
Back
Top