I upgraded the carburetor from 9.9 to a 15hp Carb with a upgrade kit close to [this](https://www.readysetboat.com/mercury-2006-and-newer-9-point-9-to-15hp-high-performance-4-stroke-outboard-carburetor.html?gad_source=1&gad_campaignid=1466323158&gclid=EAIaIQobChMIkZbNisDzlAMV4IXCCB1niDuREAQYASABEgJO9_D_BwE). Before the upgrade I was getting about 8 MPH and now I am getting about 9.5 to 10 mph I read that I should be able to get close to 12 mph. I know people think it is a waist, but I had time and money and wanted to try and now I want to make sure I fine tune it as best I can.

When I first tested everything after the swap it was running real sluggish and was smoking. after a bit of messing around I figured out the lever with the blue circle adjusted the choke and I could rotate it to the right till it seemed to lock in place which pushed and locked the silver shaft on top all the way in, thus it was in full choke all the time. When I pushed it down to its current position as shown in the picture it ran a lot better and it stopped smoking. the silver cylinder only goes in now when I push the key in when starting it. I am not sure if that is normal.

So once I figured that out I tested it again and in Idle position it was throttling real high even though the lever for the remote steering was in neutral. Initially Grok said to adjust the idle mixture screw (Screw with spring on left side circled in red) all the way in gently seated and then back out 1 and a half turns, but that made it run high in neutral so I adjusted it out as much as I felt I could as seen in the picture and the idle in neutral seems normal now.

I know my next step is to check the RPM with a Tachometer. Grok says it should have 900- 1100 RPM in Idle and 5000 to 5800 rpm with the throttle fully open. Is this correct?

So if it does not read that it said to adjust the idle speed screw, but I have no clue what that is. Grok said initially it was the spring above the blue circle, but that is just a spring that looks to stop the choke lever with no way to adjust it. Then it thought it was the brass screw under the blue circle, but that is not it so I have no clue where to adjust the idle speed screw or if it even has one.

So if it does not have one it said the only other adjustment was to change out the prop to a 9 to 9.5. Is that the best to use for my setup?

Beyond knowing where or if I have a idle speed screw any other recommendations to tweak it would be appreciated.

Fine tuning an upgrade carburetor for a 9.9 HP Mercury 4 stroke bigfoot outboard with remote steering