hi Bruce

I have just fixed a Briggs 5 horse power 21 inch deck.
cleaned valves, exaust port and muffler.
i have yet to change the bar blade to its proper position (they had it bolted on upsidedown).

it starts great, first pull.
goes through the revs nicely up and down
But...
when you listern to it carefully it seems to be missing a beat. im thinking timing ???

or maybe something else
I wait your reply
regards Frank