Thank yall very much. I am headed back to the lake today. I am pretty sure I do have the EX343 but will check and make sure, haven't thought about the engine in a while. I am currently running the bilge heater and the cabin heater. Do I still need to blow the heater out with these on? Not a big deal, I have a shop vac, just not sure where to access the heater to blow it out. Thanks again!!