Brass plug?

[george resto]

Hello everyone. I’m new here and new to boating. I brought our first boat December 2022, 7 months ago. A 2002 SeaRay 185 bowrider with the 4.3 mercruiser. I noticed after every trip we do with the boat, there’s an oil dripping from a mysterious brass plug I can’t identify.

hope you guys can help. Looks like it’s been tape wrapped by the previous owner.
What’s it for and can I remove it to put fresh Teflon tape to stop the drip? Or will all the oil come gushing out? Here’s where it is…..(it’s on the driver side of the motor straight up above the starter)

 

[km1125]

You sure that's where the oil is coming from?

That brass plug (if it's the one I'm looking at the the pics), looks like it goes into the water jacket for the manifolds. Is it possible the oil is leaking somewhere else (like a valve cover) and then running down the manifold and then just dripping at that plug?

 

[Golfman25]

Looks like a manifold drain plug. You sure it’s oil leaking. Further investigation is in order.

 

[Nater Potater]

You sure that's where the oil is coming from?

That brass plug (if it's the one I'm looking at the the pics), looks like it goes into the water jacket for the manifolds. Is it possible the oil is leaking somewhere else (like a valve cover) and then running down the manifold and then just dripping at that plug?

I agree on both counts. Your second picture (5977) looks like there's an oil stain coming down from the valve cover. It's likely that the drain plug just happened to be in the oil's path.

 

[george resto]

Thanks for the fast reply’s. I just realized there’s 2 brass plugs. The one in question is picture 5979. It’s definitely oil that’s leaving a small puddle below. It gets the starter cable and trim fluid lines directly below all wet and oily. So are you saying these brass plugs are the same as the blue plugs(and the previous owner used a brass instead of blue)
Im not sure if it’s the valve cover gasket…. I’ll have to inspect… that stain just might be a shadow.

 

[Golfman25]

Thanks for the fast reply’s. I just realized there’s 2 brass plugs. The one in question is picture 5979. It’s definitely oil that’s leaving a small puddle below. It gets the starter cable and trim fluid lines directly below all wet and oily. So are you saying these brass plugs are the same as the blue plugs(and the previous owner used a brass instead of blue)
Im not sure if it’s the valve cover gasket…. I’ll have to inspect… that stain just might be a shadow.

Oil has a hell of a way of hiding its source. I chased a leak for years. Found it by accident when I grabbed the outboard valve cover to support myself and came up with a handful of oil.

 

[Nater Potater]

Thanks for the fast reply’s. I just realized there’s 2 brass plugs. The one in question is picture 5979. It’s definitely oil that’s leaving a small puddle below. It gets the starter cable and trim fluid lines directly below all wet and oily. So are you saying these brass plugs are the same as the blue plugs(and the previous owner used a brass instead of blue)
Im not sure if it’s the valve cover gasket…. I’ll have to inspect… that stain just might be a shadow.

Is this the brass plug you're talking about? There's one at both ends of the manifold, and those are drain plugs for the water in the manifold. So, if that's the case, it goes back to my earlier statement about a leaky valve cover gasket running down the manifold.

It looks like you have good access to be able to inspect this area; get it cleaned up really well, then keep checking for creeping oil.

 

[Bill Curtis]

Is this the brass plug you're talking about? There's one at both ends of the manifold, and those are drain plugs for the water in the manifold. So, if that's the case, it goes back to my earlier statement about a leaky valve cover gasket running down the manifold. View attachment 147848
It looks like you have good access to be able to inspect this area; get it cleaned up really well, then keep checking for creeping oil.

Agreed.... Valve cover or possibly the corners of where the intake interfaces with the block and head.

 

[george resto]

Is this the brass plug you're talking about? There's one at both ends of the manifold, and those are drain plugs for the water in the manifold. So, if that's the case, it goes back to my earlier statement about a leaky valve cover gasket running down the manifold. View attachment 147848
It looks like you have good access to be able to inspect this area; get it cleaned up really well, then keep checking for creeping oil.

Yes Nater, that seems to be the one dripping oil I thought. But now I know it’s just a water plug. In the photo you can see how oily the cables and loom get. I’ll clean everything up really well and monitor my motor oil level. So there’s no way this is trim fluid then?

 

[Nater Potater]

Yes Nater, that seems to be the one dripping oil I thought. But now I know it’s just a water plug. In the photo you can see how oily the cables and loom get. I’ll clean everything up really well and monitor my motor oil level. So there’s no way this is trim fluid then?

Okay, I missed where you asked about trim oil back in post #5. It sure could be. 'Same as with the brass plug; get everything as spotless as possible, and monitor it regularly for creeping oil signs. If it is trim lines, that's actually easier to trace, as you can have someone run the trim up and down while you shove your head and a good, bright light back in the bilge. Just be sure you have some form of eye protection on while doing this. Hydraulic fluid in the eyes is a whole lot of no fun. At least, that's what I've been told... An '02 "probably" has trans fluid in it (no sure thing), so, if that's the case, wipe some oil from the lines and check for color. Red - trim: Brown - engine. Or, it could be brown for both. Crap shoot...

 

[george resto]

Thanks again guys.
So I got it all cleaned up and took it out on the Hudson today. Beautiful weather. After a couple hours running her up and down the river, I opened the engine compartment and saw the small oil puddle was back. It’s seems to be spewing all over the starter, cables/wires and even dripping down into the bilge.
I checked the oil level when getting home…. I lost half a quart.
So being on a budge…. would replacing the valve cover gasket myself be a massive job!? I am mechanical inclined where as I’ve done many tuneups and oil changes. Im not afraid to try but is there anything I should expect or be careful with?
This is a pic of the same 2002 motor in my boat. I can clearly see the valve cover because the throttle cable assembly is off.

Let me know your thoughts when you can

 

[Bill Curtis]

Half a quart is a lot for a gasket leak on the valve cover in a couple of hours. Not sure if that amount is accurate..

Try to see it the bolts on valve cover are loose, 1st. Maybe just tighten them up....

That riser maybe your only hassle changing valve cover gasket. Get some riser gaskets, too, as they will need replacing if the riser has to come off.

 

[km1125]

When you're tightening valve cover bolts, try and use the SMALLEST wrench possible. A 1/4" drive socket is recommended. Pretty easy to break them and have much bigger trouble.

And I agree with above... both that a quart would be a HUGE amount for "just a gasket leak" and that I'd try tightening the bolts first. If you have a 1/4" drive swivel socket and extensions it might be a pretty easy task.

 

[george resto]

Ok. So the risers definitely gotta come out, huh. No problem then. I’ll get those gaskets also…. First I’ll see if the valve cover needs tightening with that 1/4 socket.
You were both right… it was actually way less than half a quart that leaked. Closer to an 1/8 is what I poured back in to bring the dipstick level to “OK”
Ill let you know what happens

 

[george resto]

Good news.. I started the job. Took off 3 bolts holding the steering linkage and moved it to the side. Valve cover came right off. The riser/manifold wan not in the way. New gasket and put it all back. Took 40 minutes. I’ll get her on the water soon for the true test

 

[george resto]

Hey Bill, quick question, you mentioned a while back in the discussion that my oil leak was possibly at the corners of where the intake interfaces with the block and head. I’m not sure where you mean.. and I didn’t really notice anything there. But it still can be a possibility ?

 

[Bill Curtis]

The intake meets the block and heads at the 4 corners and the 2 different gaskets, the Intake to head gasket and the intake to block gaskets meet at these corners. That is where the problem lies, is at that junction of the head, block and intake, along with the 2 different gaskets..

The rear is most common spot for the leak. That is a very common spot for an oil leak. The fix is a decent blob of Permatex gasket maker in all 4 corners to seal those meeting points.

Been rebuilding Ford, GM and Mopar performance engines (including Hemi A/A fuelers) since the later 60's and none of them are immune to it. The blob always cures it.

PS: The Big Block Mopar wedge engine intake doesn't touch there, but the "gasket pan" does and outcome is the same.

 

[george resto]

Alright . I think I’m gonna do the water trial first to see if it was the v.c. gasket.
If it still leaks then it’s gotta be what you’re saying Bill. Permatex gasket maker
sounds like something I can do.. I kinda get your explanation..
Will I have to remove anything in the way?

I found these photos, or maybe someone has a better photo.… could you mark where I should apply it?

 

[Scott215]

None of those shows the intake manifold. No sorry the exhaust manifold

 

[george resto]

Alright. Just got back from the lake. No luck. Still spewing oil(not from the valve cover). Now I can eliminate the valve cover gasket. It’s gotta be what Bill was explaining. I’ll take off the manifold tomorrow to investigate further.