.... USCG ignition protected....

This is under an outboard cover NOT in a bilge. BTW the Mercury unit DOES NOT
have any USCG approval numbers on it either so it is no more "approved" than
something you get from the auto parts store. If it doesn't say USCG and a
number it isn't USCG approved to a boarding officer.
If you take these apart they are made exactly the same (same covers, same
gasket) except the lawn tractor has a bigger contact pad.