I have recently acquired my grandfathers 78' cajun with a 80hrs merc outboard engine and as recently replaced the stator and plugs for my merc motor.(done upon a mechanics advise) It ran fine for a couple of trips and now seems to be back where I started. Once the engine is running I must continue to keep the choke on (50% or so) to maintain idle. As I push the choke all the way forward it runs about 5000 rpm or 2/3 of maximum power. As far as I can tell all 4 plugs are working. I understand this is probably not near enough information to give a perfect diagnostic of my situation but, any help or starting places would be apreciated. Please go easy on a "first timer" and eager new learner. 