When I had the bisson muffler I could only get 5700 rpm. The slimeline gave me more rpm at the same settings. I had the vent and pulse tube crossed on the first start up. I had fixed that problem and the motor ran good at home. I will clean the carb and make sure it is secured. I have already changed plug NGK BM6F . I will also check the reeds .

Some times after 5 to 8 flips it does not start I would switch the ignition switch ON and OFF and it would pop as if it backfired without turning the prop.
I will go back to MT2 oil . I have used ams oil saber mixed at 32 to 1 for about 1/2 a tank.

Thanks Joe