I have a john deere 70 1974 with a 7 horse power tecumseh how many times to i turn the either jets on the carb

The bottom screw on the carburetor is the main fuel mixture screw, turn this "in" slowly until is "seats" and then back it out two turns. The idle mixture screw is located on the side (do not confuse with the idle speed screw), turn this in slowly until it seats and then back it out one turn. This will get you in the ballpark but it will have to be fine tuned from their. The proper adjustment is between a "lean" running condition (engine will try to cut off) and a "rich" running condition (engine will load up). The main fuel mixture is adjusted at full throttle position and the idle mixture screw is adjusted at idle speed. Once this is done, you can adjust the idle speed screw in the low throttle position. Hope this helps.