OK, maybe I'll get hung drawn and quartered for this....but i have a XTM-Xterminator XT-2 RTR with the XTM .21 engine with a pull start. It was my first every RC anything!! (still have it) I broke the pull start twice (once the exact same way you're talking about MERC) and finally gave up with it. I bought a bump starter and just cut the cord of the pull starter as close to the engine while it was pulled out all the way. Now i just use the bump starter and all is fine. Never replaced a thing on the motor (other than the plugs) and it still runs very well (it's my basher).

Maybe I'm wrong (and i've never asked) having done that rather than taking the pull starter assembly off and replacing it with a proper back plate, but everything still works fine and it starts right up. A lot easier than a pull starter by the way....[&:]