On May 15, 3:30 pm, trainfan1 wrote:
dpb wrote:
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The larger deck, though, will do it in fewer passes. This would likely
be offset by the overhead of a slightly larger engine.

I use less gas with a 18hp lawn tractor than with a 5.5hp self-propelled
mower for the same piece of lawn. It takes a lot less time too.

Don't forget the value of your time when considering a larger mower.
You always come out ahead, even if you use more fuel.
....

You're making the wrong comparison. OP was asking about the
difference in fuel consumption between to mowers of the _SAME_ size
deck, but one of significantly larger HP than the other. Therefore,
the apt comparison is simply one of whether one can drive enough
faster w/ the higher powered one to make up for the higher fuel
consumption rate.

As noted, that may (or may not) be possible depending on the
configuration of the area to be cut. If it's one big rectangular
field w/ nothing in the way, got a chance. If it's full of flower
beds and other obstacles or a very irregular area, not so much...