i have tried everyhing you can think of with this GO.21 GEN 5.5, and still geting lean bog. very very very frustrated with it, RUNNE is suppose to be sending me updated carb rebuild kit but havent heard back from him after i sent my addy to him? also asked him to send long needle? after having issues with this engine, kinda leary about trying the GX series out for next spring! or the mg66, unless they have a killer return policy! or warranty of some sort. ive never had to fight with a engine this long, im not a quit'er (fighting with it for 6 months) but this is getting alittle rediculas. i see im not the only one having these problems! with this engine in my truggy, does not even make it fun!!!