Re: Motor bogging at start up low speed
One thing no one ever mentions in these blogs is that when these things are new, they are very tight. Using gas/oil mix as specified for break in takes some time. It could be that the plug is fouling periodically, then clearing itself. Be patient. I had to go through my 2 tanks of break in fuel, change the fuel mixture to the recommened post break in ratio before the thing really started cruising. Hows 33mph!! Clocked with a gps no less.
As for the vibrations, make sure the engine is mounted perfectly straight and all the mounts are tight. Don't give up. These things are a blast!!