Chainsaw Repair

In my specific case I am rebuilding a Tillotson carb HS136C with a RK-23HS kit.
But my question is fairly general regarding adjusting the metering lever.
What effects would you see if the lever was adjusted too low?
What effects would you see if the lever was adjusted too high?

According to several youtube videos on rebuilding carbs, the lever should be level with the top plate of the carb.

Any information you can provide is greatly appreciated.

Chuck

Higher the lever on the fulcrum the more fuel through the metering needle. 

This would then effect the settings of the H and L screws in what way?

Also, can anyone tell me why the spring under the lever is never included in the carb repair kits?

I've seen kits with and without the spring,
 A worn fatigued spring will have the same affect as raising the fulcrum arm and richen the mixture across the board. In my experience its not a problem re-using the spring, as its unlikely its so fatigued it wont provide adequate pressure to seal the needle and prevent flooding.  The needle and seat condition is way more critical to proper function. Make sure the fork in the fulcrum arm isnt bent (both tangs parralel) as this will cause the needle to bind and flooding/ erratic running.

Set the arm flush and that should work fine.  Higher arm setting will generally richen the mixture necessitating turning in the H and L needles. Too low a setting will do the opposite, and needles will have to be opened to compensate. Needles will compensate for any small variation in arm height and tired springs etc

Higher the lever on the fulcrum the more fuel through the metering needle. 

Assuming that there is enough demand to open the needle fully which is unlikely unless you are running alcohol.  More likely what you are really seeing the difference from is about 2 lbs less pop off pressure.  It's about the same as cutting one flat coil off the spring.