I figured that since the 445 that I bought from Lowe's was now 7 years old, I should probably tune it up. I put on a new bar, air filter and changed the spark plug. I've recently been keeping the chain sharp too Thing is, after the plug swap it seems down on power. Before the changes, I could bury it in a cut and it would just muscle through it. With the new plug it bogs and I have to lift a little to let it recover. I put the old plug in and it runs great.
The original plug was a Champion RC7JY and the new plug is an NGK BPMR7A. I cross referenced the plugs and that seems to check out. There is an Amazon review on this tune up kit that says "Saw worked great til I put in this plug. Not sure why.". Did I get a bad plug, or are NGK plugs not good?
My only other experience with NGK plugs is in an 1/8 scale hydroplane and I'm wondering if I'm leaving power on the table there.