Exhaust leak near anode on lower unit? (150HP V6)

hkeiner

Lieutenant Junior Grade
Joined
Oct 17, 2006
Messages
1,055
While running my motor on the hose, I see that water and exhaust gases are blowing out near the anodes on the lower unit. My shop manual seems to indicate that it is normal for water to exit at this location (see quote from manual below), however it does not mention that exhaust should also be exiting at this location. I can feel the exhaust blow out when I put my hand near the anode.

I am not sure if this is normal and I am worried, of course, that I might have an internal exhaust leak that needs to be fixed. The bold circle on the attached thumbnail shows the location of the anode area that I am talking about.

Also, can anyone tell me what the other circled item in the thumbnail is for (blowup of item is labeled 1647-9147-C1)? It is located near the area of the anode and I am wondering what it has to do with the water/exhaust flow. It does not seem to have a reference to the parts list, so I can't figure out how to find the name or part number of this item.

I thought I would ask a few questions on this forum before I decide to drop the lower unit to take a closer look inside. Thanks in advance for any information on this.


Quote from Mercury shop manual:

Water exits the engine in 3 locations:
• Excess water from the wall of water exits around
anodes on the gear housing.
• A portion of the water that passes through the
thermostats exits out the tell tail.
• Water exits through two 1/8 in. (3.175 mm) holes
in the lower adaptor plate into the exhaust.
 

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Chris1956

Supreme Mariner
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Mar 25, 2004
Messages
27,036
Re: Exhaust leak near anode on lower unit? (150HP V6)

I do not think that is much of a problem. It cetainly won't cause any damage. It is certainly better that the water finds it's way out, rather than lay in there and freeeze.
 

hkeiner

Lieutenant Junior Grade
Joined
Oct 17, 2006
Messages
1,055
Re: Exhaust leak near anode on lower unit? (150HP V6)

I do not think that is much of a problem. It cetainly won't cause any damage. It is certainly better that the water finds it's way out, rather than lay in there and freeeze.

Thanks for the response. I agree that is is OK for the water to exit at this spot (i.e., near the anode). It is the exhaust gas that I am unsure about.

If anyone with a similar motor runs it on muffs in the near future, please take a closer look at this spot and let me know if you can see/feel any EXHAUST blowing out along with the water. If your motor does it too, I would be inclined to believe that this is normal. If NO EXHAUST is blowing out at this spot, then I would be inclined to believe that I have an internal exhaust leak that I need to resolve.

Thanks
 

j_martin

Admiral
Joined
Sep 22, 2006
Messages
7,474
Re: Exhaust leak near anode on lower unit? (150HP V6)

The exhaust, along with the cooling water is pretty much just dumped into the mid. From there it escapes wherever it can. When you're underway, most of it goes out through the prop. Some folks drill some holes in the mid at various places to get a unique (loud) sound. The so-called offshore mid is drilled like that from the factory. My XR4, which is specifically for bass boats, has a couple of reliefs near the top so it can idle when it's down to the cowl in the lake, which is the normal attitude when you have 30 gallons of fuel, 2 full swimming pools for the fish, 3 or 4 batteries, and 2 fat fishermen and all their tackle in the back half of the boat. You can hear it coming for miles. It has a unique sound.

If it's a deliberate hole, it's probably normal. If it's a crack, you got trouble.

hope it helps
John
 

hkeiner

Lieutenant Junior Grade
Joined
Oct 17, 2006
Messages
1,055
Re: Exhaust leak near anode on lower unit? (150HP V6)

If it's a deliberate hole, it's probably normal. If it's a crack, you got trouble.

Yes, it is a deliberate (OEM) opening in the recessed area just in front of the anode. Based upon your response, I believe that I do NOT have an internal exhaust leak and that my motor is OK. Thanks for the peace of mind.
 
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