Mercury and Yamaha both make good engines but sometimes we just get one that seems to be a little more troublesome than others. I've ran Yamahas since 1995 and although they haven't been completely trouble free I feel I have gotten good service from them. The one time I did need warranty work for a blown power head Yamaha took very good care of me. I never had a seconds trouble out of that motor afterward. Now I'm running a four stroke and have about 50 hours on it thus far with no issues. Hope your new engine serves you well.