Mercury 9.9 idle mixture screw

[thelmnation]

I’ve read there is a brass plug you have to remove to access the adjustment screw . Just wanted to get some how tos on how anyone else has removed the plug and do you have to replace the plug after adjustment.

 

[racerone]

Year / model / serial # by chance ?

 

[thelmnation]

 

[thelmnation]

2016 I’m pretty sure

 

[racerone]

What is the motor doing / not doing.------I see a plug item #13 that hides an orifice.-----A calibrated passage way and not an adjusting screw.----Yes you would have to put that plug back in.----What other trouble shooting has been done ?

 

[thelmnation]

What is the motor doing / not doing.------I see a plug item #13 that hides an orifice.-----A calibrated passage way and not an adjusting screw.----Yes you would have to put that plug back in.----What other trouble shooting has been done ?

 

[thelmnation]

I just doesn’t idle very good you have to crank it in choke every time and turn the choke off and put in gear as soon as the choke is off and engine idles down but when you throttle all the way down in gear or neutral it just sputters then dies . Runs fine when you are doing anything but idle.

 

[Sea Rider]

On newer motors due to EPA regulations the mixture screw is sealed with a alum/brass plug on top, to acces it must drill the plug out. Don't know if there's a spare part available. Anyway works OK without it.

Happy Boating​

 

[chanders]

I’ve read there is a brass plug you have to remove to access the adjustment screw . Just wanted to get some how tos on how anyone else has removed the plug and do you have to replace the plug after adjustment.

If you didn't already do this, then here's how. Get a drill and small drill bit about 1/16 inch. carefully center the drill bit on the brass plug, (careful not to damage anything). Drill in half way. reverse drill, pull back. plug will come out. I did this on a 9.8 tohatsu. Came from factory set so lean it could barely idle. Adjust idle speed and fuel/air adjustment until she sounds right.