Riverrunner 1984, I must concur with Mr. Hotwater on your boat's hesitation problem. I have seen people go crazy trying to find a hesitation problem. You wouldn't believe how many people have NEVER cleaned their flame-arrestor on top of the carb. Have your local shop just soak the thing in carb cleaner for a bit . Once rinsed off, it will flow like new again. Start there. Further, you may have picked up some crap in your carb over time. Check your float bowl(s) for debris, proper float level(s) and accelerator pump for operaton. I tend to think it's more fuel oriented over ignition, but I'm not there to know exactly. Overall, I don't think you have a major problem, just a maintenance issue. About tubing headers, ( they are cool looking aren't they), adding them to an existing state of tune will tend to "lean" the fuel mixture the engine sees, due to better removal of exhaust gasses from the cylinders, but, having just said that, will exaggerate a stumble caused by a lean mixture upon acceleration ( if that's what is happening, again, this is a guess). You may want to have your mechanic jet your carb up a few steps with headers. If you go to buy new headers, ask if the manufacturer has different sized tubing diameters to chose from. Large diameter "Racing" style headers will look bitchin' but not deliver the added kick in the rear you may want, if you have a relatively stock marine engine. Opt for the smaller -tubed header set, if offered, and, for the same price, you should get a better running engine. Just my .02 cents