At 900 or 1000 RPM load the engine to approximately 15 inches (38.1cm)Hg IMP (intake manifold pressure). This will be about 100 BMEP. On a low BTU (mega jule) engine load the engine to about 0 inches/mm Intake manifold pressure.ALWAYS VERIFY THAT ALL CYLINDERS ARE FIRING BEFORE ADJUSTING THE REGULATOR. The percentage of oxygen in the exhaust rises when there is a misfire.