My bet is something much easier to fix. How old is the gas you are running? I have fired engines that ran fine when last driven and then after sitting for a year and the gas will varnish up the valve stems and bend pushrods after a few minutes running.
Is it predominantly the intakes that are bending?
I have dumped the gas and then run a couple gallons of 2-cycle mix and then new gas and the problem clears up.
