Thanks for all the comments guys. I did line up the 2 marks before removing the old gear. Apparently what happened was I did manage to move the cam during my 5 attempts to get the gear on. Then I assumed since it went on the locating pins all was good. NOT. I removed the cover as suggested this morning & found I was 2 teeth off position. I double checked the new gear with the old one to make sure the drill mark was in the right spot & it was. I turned the crank a little until I could get the 2 marks to line up. I buttoned it up & started it. No more tractor noise or rough running. I think the problem is taken care of. This aging thing isn't helping me at all. Seems like I end up doing more things over again lately. Thanks again for the advise.