I don't want to get off thread, but there has been a problem with many OS .91FX engine and the midrange leaning because of a bad o-ring. Air has been known to leak in around the card and then the mixture would go lean. This in every case would lean out the engine and it would over heat.

In a few cases people have had some success with OS sending the engine back or asking for a replacement ring. Oter guys have replaced the carb assembly with one from Perry.

The engine is a powerhouse and LIGHT! It should be a great match for the Stinger.