I have had a quantum that hunts on a masport base - xts 60. As its one of mine, I experimented and adding a thin sheet of foam (effectively a pre filter) made the problem much better.
Widget, I was just referring to the deck, not thinking that the engine wasn't original - normally they have a 450 with pulsaprime engine from the factory. Or the newer ones have the 125cc 300 OHV series.
Now that I see the top of that engine and that its an I/C, I get that it isn't the original engine. GMC used quantums on some of their cheaper models about 10 years ago, so I subconsciously didn't give it any more thought.
I have to agree with Norm that 190cc quantum is a bit overkill on a small deck, however I can understand that that may be intentional. I know a guy who lives on a rather large 'hobby farm' type property who only uses his push mower around the fence poles where the ride on can't get. He hates mowers with swing back blades (don't know why), but had a bit of trouble finding one with a bar, and an engine big enough to handle thick grass.