I am very new to this. I have a seloc but is not much use on some things.I have a 1971 mercury 800 with wmk-2 carbs. Can I replace these with KD-4A carbs? The kd-4a are off a 1969 mercury 800 and been rebuilt.The only difference I see is the lower strainer cover on the kd-4a has a place to screw in another hose.Where does this other hose go? Or could I take the lower strainer cover off th kd4a and replace it with one off my wmk-2 so there is only one hose connection (hose connecting upper carb to lower carb)? All help appreciated.I can't find any info on these carbs except parts. Thanks Can I just plug the hose connection?