Jester's absolutely right. I've picked up .09s, .10s, .15s etc at swap meets and fleabay for very little and those old Enyas and OSs are pretty bullet proof. Mine are all great runners even if not great lookers, and the carbs are way better than the one on your Pet .099. Step up to 1968 and enjoy the technology! It'll probably cost you 25 bucks, or splurge and get a nice one for $30. One tip...the airbleed carbs often work best with a good hot plug, like Enya #3 or McCoy 59. Just switching to a good plug usually gets rid of any hesitation when advancing the throttle.

Jim