I know that the main concern should be for the difference between the clynders for compression. I just check mine and it is 101,102,101. As far as difference is concerned I don't seem to have an issue.<br /><br />But a range of 100 for compression seem really low, as my little 15HP has a compression of 120 and 119. <br /><br />Does anyone know what the compression should be on a new motor which has less than 10hours?<br /><br />Thanks