Undder no load at full revs they sound like crap some call this 4 stroking which is a good thing nice and rich its like they are holding back all mowers that are 2T do it..Put them undder load and now they can use and need all that fuel to make power and start to hum...To lean with no load at full revs sure they would sound great and rev but undder load would have no power and also blow up in no time lol...We have all been mowing and ran out of fuel just before it does and fuel leans out revs pick up quite a bit....
