ABC engines should not broken-in slobbering rich and should not let to be run so rich that they "4 cycle". If you let an ABC engine run in a "4 cycle" mode it runs too cool. Running too cool doesn't let the piston and sleeve to expand properly and this causes premature piston wear and will shorten the life and power of the engine.


During break-in they should be run rich but in the "2 cycle" range for a few minutes. Let the engine cool. Repeat that step about 5 times. Then try to peak the engine. If the engine won't hold its peak then repeat the rich "2 cycle" runs a few more times.