2002 mercury 115 classic idle and run problems

[CHADRO61]

I have a 2002 mercury classic 115 that does not want to idle. It also does not run right at WOT only turns about 4000 RPM's on a good day.
Have had carbs cleaned new plugs new fuel and compression checked not sure as to what else it could be.

also dont know what proper idle rpm is suppose to be?

Any help would be greatly appreciated before spending a ton of money at the dealership.

 

[leaky]

Have you ever seen it go over 4000 RPM before? Asking since something as simple as the wrong prop for the boat would limit RPM.

I'm not sure on that engine, but something ~700 would not be unreasonable.

Do the carbs have any mixture adjustments on them?

FYI - in that model year I'm pretty sure there is a feature where under a certain RPM it intentionally does not run on all cylinders (to save fuel). Get a good repair manual as there may be some specific trouble-shooting due to that feature you should perform.

Based on your description, assuming it was working well and now is not, I think you may have a cylinder that's not firing. Check the spark.

Jon