Ugh, another broken mount. Poly-Locs?

I had my chain just loose enuff, so as not to transmit vibration to the vehicle, and as soon as the engine torques at all, goes taught.. so the engine can't get enuff momentum to "snap" the chain, and "tug" on the frame..

Your chain is pretty loose, and when it slips around on that bolt, will be looser.. Try twisting the chain to shorten it, till you can just get a bolt started, tighten it down,, torque the motor,, and check for slop.. imho