I have just acquired a 5 HP 2-Stroke Yamaha and have no idea of it's age or what fuel / oil ratio to use.<br /><br />The serial number is 5BS 661 L 40414.<br /><br />I have used it with a 50:1 mixture but it sounds a bit rough. Should I be using 100:1 instead?<br /><br />Thanks in advance for...
