I've always used 16-18 hp units with 48-50" mower decks.
Unfortunately, new units in that hp. range come with 42" decks. To
get a larger deck, I need to get units 23-27 hp.

Does a unit in 23-27 hp. range use appreciably more gas than a 18 hp.
unit, assuming same driving speed and workload? Thx.

On May 15, 6:06 am, Windswept@home (Jack) wrote:
I've always used 16-18 hp units with 48-50" mower decks.
Unfortunately, new units in that hp. range come with 42" decks. To
get a larger deck, I need to get units 23-27 hp.

Does a unit in 23-27 hp. range use appreciably more gas than a 18 hp.
unit, assuming same driving speed and workload? Thx.

Even if you could arrange for the actual engine load to be the same
(which it may approximate), the larger displacement/horsepower engine
is still likely to use more fuel simply from the size difference.
But, in general, if you can effectively use such a large deck, the
actual _total_ fuel used can probably be kept to nearly the same by
running at a higher ground speed so the extra power can be utilized to
cover the same ground in less time negating the higher per hour fuel
consumption. If, otoh, you have to run at a low speed to avoid
obstacles or make many turns, back up, etc., and the time required is
the same you'll undoubtedly find the fuel consumption noticeably
higher.

The only consolation may be that the newer, larger engines may be
slightly more efficient. If you're going that large though, I'd
suggest at least consideration of diesel.

dpb wrote:
On May 15, 6:06 am, Windswept@home (Jack) wrote:
I've always used 16-18 hp units with 48-50" mower decks.
Unfortunately, new units in that hp. range come with 42" decks. To
get a larger deck, I need to get units 23-27 hp.

Does a unit in 23-27 hp. range use appreciably more gas than a 18 hp.
unit, assuming same driving speed and workload? Thx.

Even if you could arrange for the actual engine load to be the same
(which it may approximate), the larger displacement/horsepower engine
is still likely to use more fuel simply from the size difference.
But, in general, if you can effectively use such a large deck, the
actual _total_ fuel used can probably be kept to nearly the same by
running at a higher ground speed so the extra power can be utilized to
cover the same ground in less time negating the higher per hour fuel
consumption. If, otoh, you have to run at a low speed to avoid
obstacles or make many turns, back up, etc., and the time required is
the same you'll undoubtedly find the fuel consumption noticeably
higher.

The only consolation may be that the newer, larger engines may be
slightly more efficient. If you're going that large though, I'd
suggest at least consideration of diesel.


It's about the same amount of work, and should be pretty close. The
blades use much more fuel than propulsion, especially in non-hydrostatic
mowers, so with a larger deck there is a lot less maneuvering to hit the
next row(many fewer rows).

Rob

On May 15, 7:06 am, Windswept@home (Jack) wrote:
I've always used 16-18 hp units with 48-50" mower decks.
Unfortunately, new units in that hp. range come with 42" decks. To
get a larger deck, I need to get units 23-27 hp.

Does a unit in 23-27 hp. range use appreciably more gas than a 18 hp.
unit, assuming same driving speed and workload? Thx.

Jack,

Don't worry about it. The 23-27HP units of today are the same 16-18HP
units of days gone by.

The way the engine manufacturers rate their engines.... The size of
the horse has gotten smaller.

On May 15, 2:04 pm, trainfan1 wrote:
dpb wrote:
On May 15, 6:06 am, Windswept@home (Jack) wrote:
I've always used 16-18 hp units with 48-50" mower decks.
Unfortunately, new units in that hp. range come with 42" decks. To
get a larger deck, I need to get units 23-27 hp.

Does a unit in 23-27 hp. range use appreciably more gas than a 18 hp.
unit, assuming same driving speed and workload? Thx.

Even if you could arrange for the actual engine load to be the same
(which it may approximate), the larger displacement/horsepower engine
is still likely to use more fuel simply from the size difference.
But, in general, if you can effectively use such a large deck, the
actual _total_ fuel used can probably be kept to nearly the same by
running at a higher ground speed so the extra power can be utilized to
cover the same ground in less time negating the higher per hour fuel
consumption. If, otoh, you have to run at a low speed to avoid
obstacles or make many turns, back up, etc., and the time required is
the same you'll undoubtedly find the fuel consumption noticeably
higher.

The only consolation may be that the newer, larger engines may be
slightly more efficient. If you're going that large though, I'd
suggest at least consideration of diesel.

It's about the same amount of work, and should be pretty close. The
blades use much more fuel than propulsion, especially in non-hydrostatic
mowers, so with a larger deck there is a lot less maneuvering to hit the
next row(many fewer rows).

What's about the same amount of work as what else? No clue what
you're driving at unless you're thinking because two decks are the
same size the cutting work is the same therefore the fuel consumption
should be similar. There's a little truth in that, but it's also true
that the engine needs to run at a fixed rpm to generate the blade tip
speed and to do that will mean the larger engine will consume more
fuel. Similar as to the relative fuel economy of a V8 vis a vis a V6
both running down the road at 65 mph--both needing about the same hp
to keep then going, but the one is less fuel-efficient than the
other. Larger engine--larger carb jets--higher fuel consumption.
Didn't look to see, but manufacturers of commercial machines should
provide fuel consumption numbers.

I don't know exact percentages, but I'd venture that a significant
percentage of current mowers of 20+ hp and 48" or larger decks will
have the hydrostatic transmission which is one prime reason they have
the larger engines. That is, as I say, not a heavily researched fact
but a hypothesis based on what have observed of machines I've recently
looked at...

dpb wrote:
On May 15, 2:04 pm, trainfan1 wrote:
dpb wrote:
On May 15, 6:06 am, Windswept@home (Jack) wrote:
I've always used 16-18 hp units with 48-50" mower decks.
Unfortunately, new units in that hp. range come with 42" decks. To
get a larger deck, I need to get units 23-27 hp.
Does a unit in 23-27 hp. range use appreciably more gas than a 18 hp.
unit, assuming same driving speed and workload? Thx.
Even if you could arrange for the actual engine load to be the same
(which it may approximate), the larger displacement/horsepower engine
is still likely to use more fuel simply from the size difference.
But, in general, if you can effectively use such a large deck, the
actual _total_ fuel used can probably be kept to nearly the same by
running at a higher ground speed so the extra power can be utilized to
cover the same ground in less time negating the higher per hour fuel
consumption. If, otoh, you have to run at a low speed to avoid
obstacles or make many turns, back up, etc., and the time required is
the same you'll undoubtedly find the fuel consumption noticeably
higher.
The only consolation may be that the newer, larger engines may be
slightly more efficient. If you're going that large though, I'd
suggest at least consideration of diesel.
It's about the same amount of work, and should be pretty close. The
blades use much more fuel than propulsion, especially in non-hydrostatic
mowers, so with a larger deck there is a lot less maneuvering to hit the
next row(many fewer rows).

What's about the same amount of work as what else?

The lawn has to be entirely cut.

Each machine has to do the same amount of work for the same lawn.

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.

Rob

No clue what
you're driving at unless you're thinking because two decks are the
same size the cutting work is the same therefore the fuel consumption
should be similar. There's a little truth in that, but it's also true
that the engine needs to run at a fixed rpm to generate the blade tip
speed and to do that will mean the larger engine will consume more
fuel. Similar as to the relative fuel economy of a V8 vis a vis a V6
both running down the road at 65 mph--both needing about the same hp
to keep then going, but the one is less fuel-efficient than the
other. Larger engine--larger carb jets--higher fuel consumption.
Didn't look to see, but manufacturers of commercial machines should
provide fuel consumption numbers.

I don't know exact percentages, but I'd venture that a significant
percentage of current mowers of 20+ hp and 48" or larger decks will
have the hydrostatic transmission which is one prime reason they have
the larger engines. That is, as I say, not a heavily researched fact
but a hypothesis based on what have observed of machines I've recently
looked at...

wrote:
On May 15, 7:06 am, Windswept@home (Jack) wrote:
I've always used 16-18 hp units with 48-50" mower decks.
Unfortunately, new units in that hp. range come with 42" decks. To
get a larger deck, I need to get units 23-27 hp.

Does a unit in 23-27 hp. range use appreciably more gas than a 18 hp.
unit, assuming same driving speed and workload? Thx.

Jack,

Don't worry about it. The 23-27HP units of today are the same 16-18HP
units of days gone by.

The way the engine manufacturers rate their engines.... The size of
the horse has gotten smaller.


Reference please?

Rob

On May 15, 3:30 pm, trainfan1 wrote:
dpb wrote:
...
....
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...

dpb wrote:
On May 15, 3:30 pm, trainfan1 wrote:
dpb wrote:
..
...
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...


"To get a larger (48-50")deck, I need to get units 23-27 hp. Does a
unit in 23-27 hp. range(48-50") use appreciably more gas than a 18 hp
(42")unit"

Was the comparison I am making.

You guys must have smaller lawns than I do, I have hundreds of trees, &
there is no way a smaller deck is better than a large one under any
circumstances.

The OP is concerned over fuel usage, which really is moot when you
consider acquisition costs & your time.

Rob

trainfan1 wrote:
dpb wrote:
On May 15, 3:30 pm, trainfan1 wrote:
dpb wrote:
..
...
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...


"To get a larger (48-50")deck, I need to get units 23-27 hp. Does a
unit in 23-27 hp. range(48-50") use appreciably more gas than a 18 hp
(42")unit"

Was the comparison I am making.

But the way you quoted it isn't exactly the way OP wrote it--

"I've always used 16-18 hp units with 48-50" mower decks.
Unfortunately, new units in that hp. range come with 42" decks. To
get a larger deck, I need to get units 23-27 hp.

Does a unit in 23-27 hp. range use appreciably more gas than a 18 hp."

Pretty clearly, he's asking in reference to his current machine which
apparently is a 48" deck but at least the manufacturers he's looked at
are now not providing that w/ as low as the 18 hp engine.

You guys must have smaller lawns than I do, I have hundreds of trees, &
there is no way a smaller deck is better than a large one under any
circumstances.

I guess that would obviously depend on how the trees are arranged and
what portion is mowed...

No idea how big the mowed area is, OP didn't say. I've seen guys use
things far bigger than the area would justify simply for the desire to
have it. OTOH, I've seen other struggle along w/ a 20" pusher on
areas that might take days to get over...

The size of lawn I have seems immaterial...

The OP is concerned over fuel usage, which really is moot when you
consider acquisition costs & your time.

Guess that's in the eye of the asker, too...at pushing $4/gal it does
begin to make a visible expense. Since it now takes over $200 to fill
the tractor and during planting or other heavy use time periods that
happens every day, I can certainly understand the desire to hold down
fuel costs, even it if is just the yard...
Rob

On May 15, 6:06 am, Windswept@home (Jack) wrote:
I've always used 16-18 hp units with 48-50" mower decks.
Unfortunately, new units in that hp. range come with 42" decks. To
get a larger deck, I need to get units 23-27 hp.

Does a unit in 23-27 hp. range use appreciably more gas than a 18 hp.
unit, assuming same driving speed and workload? Thx.


BTW, if you're still around after the diversion into what OP really
said ( ), I did a quick google to see what I could find...

I did discover that several of the lesser-known, more regional
manufacturers do have what you're looking for in combination of deck
size/horsepower, most often in commercial walk-behinds, but a couple
of riders.

Did seem like the "name" guys are mostly in the bigger engine camp,
you're right. But, you might want to do some more digging into what
else is available at some of the smaller suppliers in your area.
Around a lot of the commercial guys use Grasshopper stuff...

In article .com,
(dpb) says...

The only consolation may be that the newer, larger engines may be
slightly more efficient.

I hear the newer engines with pressure oiler systems are a LOT more
efficient.

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