I just got done completey disasembling a stihl 031av that I bought off ebay to install all new gaskets and seals. The saw had this problem before I took it apart. The saw will only rev up to 11,200 rpm before it gets so lean it begins to bog down. THis is without the bar. THe spec is 12,000 rpm. When the bar is installed i set the saw by ear. When it starts to 4 stroke its running about 10,000, well below the 12,000 spec. shouldn't the saw be able to rev well about 12,000 when its set to the full lean setting. The only thing I haven't checked is my fuel filter. It starts and idles and runs good. Compressiom is at 150psi. I havn't used it to cut anywood because I wanted to set the carb with a tach before I used it. Im using a wirelss digital tach that is accurate. The saw is the electronic model and carb was rebuilt by the guy I bought it from. any ideas.