Have an 88 Johnson 110 with same choke. Just got the boat late last year and it hadn't been run much by the previous owner for a couple of years. Had trouble at first getting started. Thought I may have gotten a lemon, but soon discovered I was choking way too much. Had the engine checked out, and actually is very strong. Just inexpierence with the engine and too much key pushing. It would flood and then batteries would run down and no go. So far this year, no problem. good strong batteries are a big help.
I had a problem with my (then) two year old 50 HP merc. I had just changed out the fuel water seperator (exterior to the motor) and although it ran 30 minutes earlier I could not get the motor to start at all. Good spark, plugs wet with fuel.
When I called Dandy Haven Marina about bringing it in for repair, the mechanic told me to remove all of the plugs and crank it for 30 seconds to clear the fuel which builds up (somewhere inside the engine, I don't remember where) when you flood it, or should I say over-flood it. Sure enough when I replaced the plugs it started right up.
All the engine needs is quick squirt to fire. Once running give it another quick squirt as it starts to die. You should only have to do this once or twice since the fast idle lever should give it enough fuel to keep running.