Hi and thank you for your question.
Any fuel leak is a huge safety concern. Ventilation can be minimal under certain conditions and create a fire or explosion hazard.
I suggest you give a very close inspection to the carbs and fuel lines on the affected engine. There is a good possibility the bog is related to the fuel leak also. I suggest pulling the carbs off and taking them apart so you can get a good close look at everything and determine exactly where the fuel is coming from. Boat carbs, and especially the pumper style carbs like the 1100 engines use, do not vent fuel chambers to the atmosphere. The only atmospheric vent on the carb is on the back side of the diaphragm for the needle valve, but the diaphragm separates the fuel from the atmosphere.
Here is a link to a diagram of the carb assembly and also the mounting points too. If you have a shorty 12 mm ratchet wrench it can ease the removal of the nuts in between the center and outer carbs. Ratchet wrenches in general help speed up the removal process.
Once you determine the nature of the fuel leak, give careful consideration to the possibility that the other engine may be close behind in experiencing the same problem.
I would suggest doing a compression test before removing the carbs just to make sure the engine is mechanically sound. If we have a mechanical problem, we want to know about it before we take the carbs apart so we know to look for a cause of that mechanical problem during dis assembly.