How to ajust my cobra 29 to so it will get out to talk

First check the swr's. make sure you have a good antenna, like the 108" whip, others will limit your range, because they are shorter, stay with the longer 7ft types like the predator 10k, or wilson 5000 magnetic mount.
Then just adjust the modulation variable resistor for minimum resistance and it will let your radio have full output power. No cutting!!! Check it with an oscilloscope and watt meter, and check the frequency with a freq counter.
Other things, good quality echo mic. or power mic (cobraHM75$17.99), or even a RK56mic($38.99)...