Chainsaw Repair

On my machines 2150...The high idle button only functions until you blip the throttle and is for starting.
The choke lever resets if you push the ignition kill switch or if you push it off manuall..
I think my older 3800 has a high idle cam actuated by the choke... not the same. push the choke off ...idle comes down...
The 2150 oil pump seemed slow to oil and I swapped it with another basket case piece....it seemed better but I tried to figure why??? and did not see how the oil is made to move.  No one could explain it either... at least so I could understand.
Never could figure why some have the exhaust insulator and some don't. I don't loose any sleep over it though!