carb idle speed help

[ex21mini]

today the the first nice day this year i could ride. i am having prolbems getting my idle rpms below 2200. i have a pz22 and ive tried turning the screw in the middle of the carb in and out a couple turns and nothing? but when i was running the engine off of the bike i could get the rpms down to 1600 rpms? any ideas

 

[jeep4me]

What make of engine? Pics of throttle linkage hooked up on the mini will help too.

 

[ex21mini]

robin subaru ex21 7hp ill try taking the throttle cable off maybe there is to much tension on it?

 

[ex21mini]

took throttle cable off. no luck? i can see the slide move up and down when i take the air filter off and turn the screw in and out. but no changes in rpmsut:

 

[jimh]

Sounds like the mixture is too lean, either From the air screw backed out too far or an intake leak.

 

[ex21mini]

thanks jim that seemed to work a litttle better. how do you guys no when your engine has the corrrect air\fuel mixture.spark plug color after 30 min?
also what could cause backfiring when i let off the throttle at high rpms?

 

[jimh]

If you're running a header or straight pipe, youll notice the backfiring worse. It's the unburnt fuel igniting, change in exhaust pressure and velocity,etc. That backfiring is not as noticable with a muffler. It just sounds like little
"putt- putts" The plug should look dry and a brownish gray color, but not always. They kind of get sooted up when choking to start.

 

[ex21mini]

thanks:thumbsup: