Welcome Diesel to BGW
From the look of the pic first you would be mixing the fuel at 128:1 or 1 oz per gallon as it looks as though the oil injection has been removed. Mix it in a fuel jug first before putting it in the tank. Next the throttle cable the one with the throttle stop should have a spring behind it between the stop and the throttle arm. The spring should be loaded or compressed as to fully close the throttle when off the peddle. Start there and report back. Some has used a simple ball point pin spring to get by
LOU