The Chevrolet S 10 pickup truck idler arm can be removed by removing the idler arm retaining bolts. The idler arm has two retaining bolts. Reverse the process to install the new idler arm.

Remove the nut holding the idler arm to the center link. Separate the joint with a "pickle fork". Remove the two bolts and nuts from the frame end of the idler arm. Remove idler arm.

How much torque do I use to tighten the idler arm

Wasn't aware a Merc 190 had an idler arm. However, clunky steering and wander. Observation of the idler arm will show excessive lateral movement

No, there is a pitman arm on the steering box and two idler arms on the linkage.