What mower exactly? If 7.0 is HP I'm guessing self-propelled walk behind?
Anyway how old and how many hours on it? Have you done regular maintenance like clean the air filter, put fresh fuel in, check and change spark plug as needed?
Default guess is your carb is gummed up. If that's the case you could try some fuel system cleaner (Techron, etc) at double the labeled ratio (then run a tank of fuel to give it time to clean), or get a carb rebuild kit then clean and rebuild it, or a whole new bolt on carb.
Could be something as simple as the carb mount bolts working themselves loose which could just mean they need tightened or if it was ran this way mowing, some grass/dust/debris/etc could have made its way into the carb gasket and it needs cleaned off or just that gasket replaced... but might be easier in the long run to just get a full carb rebuild kit and do the whole thing at once.
Otherwise examine the engine. I've seen cases where someone banged their mower into a bush and bent the throttle lever, or a rubber push-bulb primer was cracked and changed fuel flow, as would a cracked gas line, clogged fuel filter.