hello,can anyone help me with an evinrude engine,1988 15hp, which is a pig to start.after 15 minutes of sweat and swearing the engine will fire up, runs like a swiss watch, thro' to full revs,idles great. when i switch it off, it will start again with the slightest pulls. leave it for an hour or so and its back to sweating and swearing.can any of you fine people offer advice. thanks for reading.