Gensep Generator Exhaust Water Separator Issue

We have a gensep box on our generator exhaust that separates the exhaust gases from the water as it exits the muffler. The water is supposed to exit a thruhull below the waterline, and the cooled exhaust gas exits an above waterline thruhull. It has worked great and is very quiet. However, last weekend I noticed water splashing out of the above waterline thruhull. I know this will happen if you block the below waterline thruhull, but I've never seen it do it unless I block it on purpose. I wasn't in a position to inspect last week, and plan to try and figure it out tomorrow. In the mean time, has anyone encountered this issue? And, if so, any pointers?

Did you do anything lately to the generator lately like a new impeller or exchanger cleaning lately? Reason I ask as soon as we did that we noticed a little water coming out of ours. Not much but definitely more than in the past.

You almost certainly have marine growth or critters partially blocking the water exit thruhull. Hook up a water hose and try blasting it clear. Or rod it out.

David

Capt. Jon said:

Did you do anything lately to the generator lately like a new impeller or exchanger cleaning lately? Reason I ask as soon as we did that we noticed a little water coming out of ours. Not much but definitely more than in the past.

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Over the winter we removed and cleaned the heat exchanger (which it turned out didn't need it), replaced the heat exchanger end caps, replaced the exhaust mixer, and installed a new impeller (old one came out in one piece). We have probably ten hours on it since that work and it was this weekend for the first time that it started acting up. Now that we are back at our floating docks and I can reach the below water thruhull I may try to give it a blast from the hose. I'll be very careful not to let the muffler back fill into the engine - it should exit the above waterline thruhull before that happens, but I'll still be careful.

If you are going to blast water into the water drain fitting, do it with gennie running. Can't flood gennie that way.

Good point!

Those units (Centek Separator) are very simple, not much to go wrong inside. So the consensus is probably correct that there is a drain blockage of some kind.

Does the below-water outlet have a seacock? Is it fully open?

Shoalwaters said:

Does the below-water outlet have a seacock? Is it fully open?

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Yes it does, and yes it was opened. I tried blowing some water through as discussed with no change, also opened and closed the seacock a few times. Had to leave the dock as we had weekend plans and wound up running the genny for at least four or five hours over the course of the weekend. By Sunday morning it was working fine, so whatever was in the line must have worked its way out.

I've had fish camp out in un-screened through hulls. Sometimes they get stuck when flow starts. Sometimes they get annoyed by the flow, are not stuck, and leave on their own.