Hello Robert, may be you can offer some advice to me about my 15hp 2 stroke Yamaha outboard. My problem is that when I start the outboard it will idle OK, but when I advance the throttle the engine will run rough and cut out. I have replaced the Carburettor, CDI unit, high tension coils and leads ( all off another motor that is functioning quite well) and the same problem occurs. I would appreciate any advice on how to eliminate the problem. It becoming quite frustrating. I would appreciate any help that you can offer.