i was running hotlaps n a buddy put 18 oz. of oil in my engine. didnt know till after race. seen it was leaking oil from round the cranking case,then i drained all the oil out put 13 in it. started feature, an was running some what sluggish, would that seal leak be making it loose that much hp? my mph was off by 1.5 if i re-plced the seal would it fix it or would the engine need to be re-built?