It is difficult to succeed with the solution to your problem, give few data. Keep in mind that it is a rather greasy engine to start it. First adjust the decompressor cable according to manual, after once the idle is plotted, it is an important adjustment to put these engines, in cold you have to start with being and without giving any gas. In hot you do not have to give gas, you abose only a little. If it still does not start tendergas little compression and that is already more serious. Tamia rings, adjust valves, rctify cylinder.
I hope I have helped you. Sincerely Josep.