If you use 50:1 your machine will run a lot cleaner and will not clog up your muffler with carbon anymore. Most small engine shops use 50:1 in all 2 cycles engines. Including my shop.
Mr. De Board, July 2008
A 25:1 petrol / oil mix will suit you fine. Use a good semi synthetic oil such as Oregon - its bright red so you can be sure you are actually using an oil mix!
