The 152 I fly has some difficulty starting. THe engine has about 1000 hrs, good compressions. Just out of annual. When starting, it will occasionally "pop" when cranking over and then will catch and stumble along on its own for a bit. Repeat this once or twice when it's cranky and it will finally fire up. Once running, it runs very well. Any ideas? I have flown 5 different 152's and this is one of the more difficult ones to start. The owner asked the mechanic to address this problem at annual, guess it did not get solved.