For your Throttle problem, you might search for the measurement that is needed in the linkage. If its to loose you'll have these symptoms. The end sockets have a tendency to ware and gets out of adjustment. I believe Genos garage has some of these parts now.
I have found that the batteries need a good charge/connections to pull the solenoid up to start also. Its just a group of things that need to be maintained.
All new linkage, return spring, accelerator cable adjusted exactly to service manual spec (5"), no binding. New batteries last week.