Most Peoples issues with carbs today, is from running fuel with ethanol in it. If you do, DO NOT store it with Ethanol fuel. It goes stale quickly, absorbs water and you will have corrosion in your carb. Older engines fuel system were never designed to run on it. It can eat the fuel lines and rubber parts. In Nanaimo you can buy 91 marked gas at the co-op. That's all I use in my boat.
Tohatsu makes merc's smaller engines. Better warranty with Tohatsu as well.