I have a Saito 72 that I bought used (this might be my biggest problem). The engine has given me quite a challenge to get running properly. the previous owner I feel knew nothing about 4 stroke engines or engines in general and both the low speed and high speed needles were way out of adjustment. I finally got the engine running what I thought was good only to have it quit running all together after 5 or 6 good flights. I took the rocker covers off and I noticed one of the pushrods was no longer "seated" into the bottom indent of the adjustment screw. Is this something that happens from time to time or does this mean I have another problem, possibly a bent pushrod? I don't believe it would be terribly hard to replace a pushrod , they just drop in after removing the rocker arm, am I correct here?