340 invader idlei

[norm]

I have a 340 invader that I installed new choke
plungers. I have the idle set at 3000 rpm it will
Idle just fine,but when I engage the clutch and let off the throttle the rpms drop to around 2000. And  will remain there till I tap the throttle then it will go.back to  3000
rpm till I engage the clutch. Is this normal, any help would be greatly appreciated.

[Interceptor398]

Not normal,  has the sled warmed up all the way?

[norm]

 Yes,temp gauge reading 170.

[Checkmarks]

Sounds like the idle air mixture is wrong.  The first thing I would check would be the if carbs are in balance.  After started and warmed use the vacuum off the primer nipples.  Use a 5ft hose 2.5 off each nipple then use a larger diameter hose say three feet bend in a U shape with each carb hooked into system.  Use gravity to keep the fluid (colored water, mercury or antifreeze) in the larger tube.  When the motor is running the water should be in balance between carburetors.  If not use the set screw that lifts one or the other throttle valve.

Balanced carburetors are not just a "2.5" turns in from just touching the throttle valve.  Balanced carburetors are not an equal throttle valve opening.

 Balance carburetors are equal in sucking down charged a/f.

When you have it right the sled will start like a champion when the idle fuel screws are correct.  Getting idle set correctly (rpm) must include balanced carbs.  Play with the throttle valve screws trying to get the rpm up or down requires hooking up the balancing system again.