May be due to accelerator pump. When governor throws throttle open, you should get a squirt of fuel at same time. If not, then may be accelerator pump is bad, or linkage to it has fallen off. Another thing that can cause this is an air leak on intake system. Minor leak can cause bog down in heavier grass, then seems to go away in lighter cutting. Float level too law can cause it too.I purchased a used Toro Recycler 22" Self Propelled mower last year. It has the Tecumseh engine, 6.5 hp, 195 cc, Model LV195XA.
It has always bogged down too easily. I've tried replacing air filter, new gas, adjusting idle speeds, etc. But nothing so far has solved the problem.
Other than bogging down (on not very high grass) I like this mower. It completes the job, just have to go slow when it bogs down.
One less thing to go wrong then. Fewer places to look is always a good thing.There is no accelerator pump on this engine.