It depends on what year. Some, it’s the carb. Others, it’s the carb and a tuned exhaust. Others have a shim for the reed valve….You have to look pretty closely to find all the tiny stuff.
Yes indeed, many little differences depending on the year…. You will pay big bucks for a 15hp carburetor and may not see much, if any, performance increase…So many factors to consider. I would leave it alone…
