Merc 2012 6 hp 4 stroke Idle issue

[4now04]

I am the original owner of a 2012 Merc 6 hp 4 stroke that i use on an inflatable. Last season and during part of 2018 the engine did not idle properly. It would eventually load up and die. If I briefly opened the throttle to clear it and then closed the throttle completely the engine would run at a very fast idle speed for maybe 30 seconds or so before slowing down to a more normal idle speed. I have disassembled and cleaned the carb 3 times with no difference. The throttle closes completely. Any ideas? This is the same engine that is marketed with the Tohatsu and/or Nissan decals on the engine cover.

 

[Texasmark]

I am not familiar with that engine, nor 4 strokers at all. I do know that 4 strokers used in a lot of trolling and cold winters develop condensation problems, like oil level in the crankcase rises....due to condensation. Point here is that you may have a fuel/water problem.

Something you might try is to pull up the process: Decarb.....either in the archives herein or just google the word. Perform that procedure and then change your oil and get fresh fuel and new spark plug(s) and see where you are. Won't cost you that much and may be time to change both anyway. Check back.

If nothing else my reply will bump your question back to the top of the list and will be easier for knowledgeable folks to catch it and reply.