Adjustment screw on metro carb - what's it called and what does it do?

[slash5bmw]

Anyone know what this screw is on an exmark metro 36 carburetor. It's right next to the pilot jet. This isn't the exact carb but it's very similar to mine.
You can only access the screw when you pull the carb.

Thx
J

 

[Scrubcadet10]

that is most likely your idle/pilot mixture screw. Screwing in usually leans out the mixture, out makes it richer, i usually adjust them on a warm idling engine to the highest RPM point, then the main idle screw on the butterfly to set idle RPM.
You have to be careful with some of them, if you screw it all the way out to remove it, it will break off... i didn't know that the time, but it's made that way..

 

[slash5bmw]

Thanks. There's a little metal tab on the side of the screw. I'm not sure it's able to go all the way in or out. The screw faces the engine side and is not accessible. To access the screw I'll have to remove the intake where the air filter sits on and use some spacers to get the bolts to hold the carburetor on. I then might be able to adjust the screw with the air filter off and the engine running.

I wish they had the screw on the other side of the carb.

 

[Scrubcadet10]

yeah that's an anti tamper screw. Environmental regs.