ORIGINAL: Fastsky
4 strokes don't sound much different between slow idle and full rpm so its difficult to adjust the carb properly without a tach.
Where do people come up with this stuff???
Fast, no offense, but get your hearing checked.
I have lousy hearing (I rarely hear ANYTHING my wife says
) but I still have NO problem tuning a 4-stroke "by ear".
In fact, I bought a tach a while back (just so I could take a picture of it showing the RPM of an engine I was reviewing) but I wouldn't even THINK of using it to tune an engine.
bbellfish, get yourself a 4-stroke - I like OS over saito, but it's a ford/chevy thing. Get a 70 for a 40 size plane or a 91 for a 60 size plane and you'll be as happy as a pig in slop.