Hey guys so I just purchased a evinrude 9.5 1971. When the guy I purchased it from demoed it for me I noticed that it started fine cold start on first pull. Compression test was good, spark plug wires look brand new and plugs. Engine looks amazing overall like it has very low hours. It started to misfire a little bit then start running fine . Owner said the gas was a year old and it definitely looked and smelled old. Could this be the reason for this misfire ? Should I do a carb rebuild or just try to run some sea foam first to see if that clears anything up.