It's possible one cylinder isn't firing. At idle, sometimes it's hard to tell. You can check while it's running with one of those neon spark test lamps.I have a 45 hp Westbend.... starts right up...Idles great!! When you give it gas it boggs down...then levels off but tops out at only 5-8 mph....has no power.... any ideas?? I am new to outboards!
Thanks!
Welcome to Iboats!! First things first, check compression, spark, and fuel delivery. It sounds like you need to clean the carb/carbs, rebuild the fuel pump (easy and cheap), and make sure your getting spark to both cylinders.