Using a conventional tachometer on a diesel engine, it is impossible to adjust the idle speed. A special device must be used to accurately control the idle speed. An experienced motorist can change the speed by ear if the diesel rattles or vibrates a lot.
1. Loosen the locknut on the adjusting bolt.
2. Adjust the RPM: twisting decreases RPM, tightening increases idle RPM.
3. Never turn the maximum speed adjusting screw!
4. The optimum idle speed is 825-875 rpm.
5. Tighten locknut.