2001 merc 4stroke 90hp idle issues

I have a 2001 merc 4stroke 90hp. I am beginning to have idling issues, especially when trimmed up. I have the service manual and have cleaned the carburetor enrichener circuit and that has not helped. It all started when I ran some carb cleaner through it. It is idling low and dieing constantly. If I lower the motor back to the horizontal position it takes a second but it will start idling decent, but it takes a little while.

The fellow I bought the boat from told me to pump the idle lever 4 times or it would not run worth a flip....and that has proven to be true. On other merc outboards I have been around if you push the key in when starting that is the choke. He told me not so on this model. Details?

A lot of carburetor cleaners dissolve plastic and rubber. Not a good idea to spray in the carburetor when some of the parts and are made of dis-solvable stuff. Much better to take the carburetor off, disassemble, and clean parts made of plastic/rubber in appropriate solution and the metal parts in carburetor cleaner. If it is running worse, the carburetor cleaner may made your carburetor issue worst.

Sorry, I don't have any knowledge or experience with the 4 strokes, so I am no help to you. All I could offer was my simple statement above.

I added the stuff from gumout that you mix with your gas for marine engines.

I had a problem with my little 25hp. I got the carb cleaned and it would run great for a few weeks then would spit and only idle on 1 cyl. It would run on 1 cyl till about 1/2 throttle then the other one would kick in. After the 2nd time I knew it wasn't a dirty carb anymore, I had another inline fuel filter put in and it was catching pieces of plastic and stuff. Turns out there was a little plastic/rubber diaphram in the plastic primer twist and pull handle doodad.....It was coming apart after all these years due to fuel and ethanol breaking it down. Ordered a $10 dollar part and the problem was fixed.

Try replacing any old rubber or plastic peices in the fuel line/system. My motor was a 1999. 12 years is a long time for anything rubber or plactic to be in contact with petroleum products and hold together. Combine that with sun,salt,rain and vibration Im surprised they even use it at all on an outboard. If yours is a 2001 its 10 years old. It could be the same problem...Its worth checking it out anyway. Good luck.