Hey i need some suggestions i got a 1971 i believe mercury 20hp the serial number is 7109596 anyways heres the deal the thing will start up just fine and high rpms sounds great with no misses or stumbles but when brought down to idle it seems to miss/ cut out, it will knock itsself down and almost kill and sometimes it wont come back around and it will die. The carb has been gone through cleaned /blew out with air compresser several times replaced fuel pump dia. gaskets, inlet needle idling tube took out and everything cleaned. Tried adjusting the idle screw it seems to be non responsive until either backed way out or screwed way in. The primer ball stays hard. Another werid thing is i dissconect one spark plug and it starts right up and idles normal without any stumbles or backfires on one cylinder and just runs good and sounds good, it doesnt matter which cylinder i run it on it runs good it seems on only one is that normal i wouldnt think so but? Also got good spark and good compression cylinders within 5 of eachother. Thats about all the things i can think of that ive done so far any comments or suggestions will be appreciated
