run a brake cable to the engine, and somehow attach the brake cable tot eh old throttle cable.
I snipped about 3 inches off the original throttle attached that to my brake cable by winding a length of solid copper wire around both the new and old for about one inch and 1/4 inch thick. Then I soldered the whole thing together.
I have also used electrical wire crimp tube- slide each piece through and crimp the dickens out of it. this worked well at first
And I have also ziptied the cables together..... this actually worked really well until I soldered them together that hasn't budged yet and will be my go to attachment for the future.