My Generator is Washing my Bilge

[estoltz]

I'm 2 weeks into a 2006 340 DA and am running into an issue. We recently went out only to have my high water alarm go off shortly after leaving slip. I pull up to the fuel dock and check and my bilge is filling with water. We determined that the rear bilge pump check valve has jammed shut. However we couldn't figure out where the water was coming in. Finally we found it. The generator siphon break is pumping water into the upper starboard area of the bilge. The technician has already checked and replaced the little duckbill valve in the siphon break and it keeps pushing water in. We've determined that water is coming out of the exhaust at an acceptable level and to double check I blew through the exhaust side and don't have any detectable pressure but obviously we are getting enough to turn that duckbill inside out. The break is mounted just below the deck so I'm not sure if it can be mounted any higher. Does anyone else have any thoughts on this? Could the manifold be going bad?

Our technician reached out to Kohler and unfortunately the Marine Tech was at the Ft. Lauderdale boat show. The industrial power Tech recommended putting an acid wash down the exhaust side in case something was clogging it up. No improvement.

Thanks in advance

 

[Bt Doctur]

If you have to have a check valve on the outlet for a bilge pump, you definitrely have a design problem

 

[Bt Doctur]

http://www.wilkey.org/blogs/alegrias/Documents/Kohler/Kohler Siphon Break Kit.pdf

 

[estoltz]

I guess tell that to Sea Ray and the ABYC. That being said I have a straight pipe replacement in my spares now. My big concern is the generator at this point though.

 

[Bt Doctur]

Almost all exaust risers should be atleast 13 inches above the water line. That's what prevents water from entering the exaust system. any hose connection even near the water line must be SS or bronze thru hull. Anything else can be plastic.

 

[estoltz]

http://www.wilkey.org/blogs/alegrias/Documents/Kohler/Kohler%20Siphon%20Break%20Kit.pdf

Yes that's the piece we are having issues with. That tiny duckbill keeps turning inside out.

 

[fwebster]

Sea Ray uses a check valve in the bilge pump exhaust hose not because t hey are required, but to keep a hose full of water from running back in to the bilge sump when the pump cycles. The check valve Sea Ray uses is a Whale product, costs about $15, and has a flapper inside that frequently either gets debris from the bilge sump caught in it or the reeds dry out and curl up preventing them from working.


The reed assembly on the Kohler siphon break tends to get stuck open with either salt deposits or crud from evaporated sea water. You might try taking it apart and cleaning it before you start throwing money at it changing parts.

 

[bankyf]

Sea Ray uses a check valve in the bilge pump exhaust hose not because t hey are required, but to keep a hose full of water from running back in to the bilge sump when the pump cycles. The check valve Sea Ray uses is a Whale product, costs about $15, and has a flapper inside that frequently either gets debris from the bilge sump caught in it or the reeds dry out and curl up preventing them from working.


The reed assembly on the Kohler siphon break tends to get stuck open with either salt deposits or crud from evaporated sea water. You might try taking it apart and cleaning it before you start throwing money at it changing parts.

My bilge pump check valve is a floating piston design and estoltz should have one of the same design. Easy enough to clean out, but if I am doing any bilge cleaning, I will typically put the straight pipe in it's place. I also recently purchased a screen for Rule pumps that sits under the pump to keep any debris from getting to the check valve. Seems to work very well so far. As for sea water crud or salt, his boat is a fresh water boat and I do not believe it has ever seen saltwater.

 

[bankyf]

After thinking about your issue quite a bit, it absolutely has to be some type of restriction beyond the siphon break. I believe an exhaust restriction could put enough back pressure on the system to cause your issue as well. Although it has never happened to me, I have heard stories of critters climbing up the exhaust outlets and building nests in the muffler. Any chance of something like that?

 

[estoltz]

After thinking about your issue quite a bit, it absolutely has to be some type of restriction beyond the siphon break. I believe an exhaust restriction could put enough back pressure on the system to cause your issue as well. Although it has never happened to me, I have heard stories of critters climbing up the exhaust outlets and building nests in the muffler. Any chance of something like that?

It's quite possible. I read the service bulletin SB-662 and 692 which reference a clogging catalyst on the exhaust but that only applied to salt water boats. This boat has been stored in fresh water with only a few trips to salt water since new. As to critters I guess it's possible. We will have to pull the muffler I guess is that an out of the water process?

 

[bankyf]

It's quite possible. I read the service bulletin SB-662 and 692 which reference a clogging catalyst on the exhaust but that only applied to salt water boats. This boat has been stored in fresh water with only a few trips to salt water since new. As to critters I guess it's possible. We will have to pull the muffler I guess is that an out of the water process?

06 is a catalyst generator? Are you sure about that? Muffler is an in water, very easy job on the 340. In fact, you may even be able to just pull a hose and look inside with a flashlight. I am not very familiar with the catalyst system on a marine generator, but I suppose a melted catalyst could cause the backpressure that would result in what you are experiencing.

Edit: I see that it is, in fact catalyst. Didn't realize they went to catalyst that early. So, it seems that a clogged or damaged converter is another possibility.

 

[Sublimetime]

Any chance that this unit overheated at one time. When I removed my genny exhaust hose and muffler it had signs of heat damage. The inside of the hose kind of separated from the outside layer of rubber and it had large blisters inside causing the inside diameter to be much smaller and restrictive.

 

[estoltz]

Any chance that this unit overheated at one time. When I removed my genny exhaust hose and muffler it had signs of heat damage. The inside of the hose kind of separated from the outside layer of rubber and it had large blisters inside causing the inside diameter to be much smaller and restrictive.

That's a possibility based on a conversation with the previous owner. Looks like I am going to check out the exhaust.

 

[bankyf]

I definitely feel like you are going to be looking for something causing excess exhaust back pressure more so than a water line restriction. Let us know what you find.

 

[estoltz]

Well the verdict is in. The catalyst was clogged. It was able to be cleaned and is now operational. Thanks for the advice.