Briggs and Stratton
I am suspecting loose valve seat/s as I have had that problem with another mower almost exactly like this one only years older and years ago. To be honest, however, this one really is totally worn out and should have been salvaged years ago on it's own demerits but it does cut very well and when it's running is perfect for my property. I would gladly purchase a new one if I could find one at a decent price.
Sears sells a 13.5 HP (Tecumseh)30" one made by MTD. It doesn't hold a candle to the quality or handling of this old Murray and it is about $700 high on the price!!!!!!!!!!!!!!! The old Murray mowers sold for $499 to $799 and the Sears rig is $1500. Considering that other mowers with much more horsepower, much wider cuts, many more amenities and stronger reputations start at about $899 I think the Sears MTD rig is just out of it's league and price range. I am considering a Snapper but again, they are really proud of them!!!!!!!!!!!!!!!!!
Thanks for asking bout it!!!!!!!!!
Psychoblues