Hello all, I was given a 1968 Merc 3.9. Previous owner said it wouldn’t idle. So far I completely disassembled and cleaned the carb. Replaced all fuel lines, replaced a leaking fuel pump and a new spark plug. It starts easily but dies eventually when idled down. If you keep on the throttle it will keep running but once it stalls you need the choke every time to restart. I’m not at all familiar with a Merc carbs so did I miss something? Possibly a passage I didn’t see? When you hold the throttle in the start position it runs wonderful but once it’s turned down to the shift area it eventually stalls. Thanks in advance for your help. Dave