View Full Version : Gas vs Diesel Real World Estimates

07-11-2007, 01:11 AM

I am sure some of you commercial guys have replaced your gas ztrs with diesels. And since you have mowed many of the same yards with both, can you give me an estimate of your fuel savings? Any input greatly appreciated. Thanks in advance. Don

07-11-2007, 01:48 AM
not big on mowing residental homes but having used Toro's gas ZTR vs Toro's Kubota Diesel ZTR. We can run the Diesel on about 5 days vs the Gas which was about 2-3 days before filling.

Diesel's cost more hands down for purchasing, repair, and also are limited to a few select models. But they are worth it. With proper maintance they will last longer. They don't bog down in long wet grass conditions. Have more weight over your axle. Also better resale value.

My opinion if you have the finances to purchase a diesel instead of a gas do so.

David Gretzmier
07-11-2007, 01:56 AM
do a search on diesel, I've run the math before comparing consumption of off road diesel to gas and prices. you can save about 12,000 bucks using diesel over gas at 2000 hours of use at around 3 bucks a gallon for gas. fuel consumption is typically less than 1/2 of gas. more so in the big block- 32 horse and up gas vs. diesel.

07-11-2007, 03:41 AM
hello, around 1 gallon per hour depending upon conditions and deck size . This is on a 12mph machine 60 deck average to poor conditions . The smaller engines eg walker diesel ,tiny grassopper etc etc run around .8 gallon +/-

Not much less than gaser but typically consumption is lower for given application .
Best comparison would be carburetor big block on a large deck 66--72 compared to a diesel .
Until there is some feed back on the B/B gaser fuel consumption i would be cautious .
The larger the gaser and deck size the more important fuel injection becomes

The larger the gaser the more desirable a diesel becomes [depends on application ]

For those of u who interupt YES there is mid size diesels that weigh less than a gas unit walker grasshopper dixion ,apparently a small hustler soon [have not checked in a while] [to small IMO


07-11-2007, 09:46 AM
A BIG thanks to Swampy, David, and tomo for your input! Take Care, Don

07-11-2007, 10:24 AM
Ive got a 30 hp kohler with a 66 deck and burn 1.3 gallons per hour. That means 1 dollar more per hour for gas at 3 dollars per gallon. That also means only 2000 more to run mine over the course of 2000 hours than the deisel. Think it over carefully before you plunk down your money on a deisel.

07-11-2007, 04:23 PM
Delphied, I believe you're using "fuzzy" math. I've got a Steiner 230 with a 72" deck/28 hp Kubota diesel that uses no more than .7 gal/hr. If you're comparing this to a gas machine @ 1.3 gal/hr over 2000 hours it's not even close. Our local prices today are gas($3.30) vs. diesel($2.72). Steiner 2000 hours x .7 gph x $2.72= $3808. Gas machine 2000 hours x 1.3gph x $3.30= $8580. That's a difference of $4772.00. That doesn't make gasoline look very good does it?...One can deduct even more by using off road diesel which is 17 cents cheaper here in Missouri................Lynn

07-11-2007, 04:48 PM
Good point gorrell, but diesel is also more expensive up front to purchase. You do get a better resale with that diesel though. Are these smaller diesel engines (20-30hp) more expensive to maintain than a similar sized gas?

07-11-2007, 05:06 PM
hello, considering diesel against gaser
kohler gaser ,inlet maniflod vacumn leak, coil failure ,head gasket [s] ,valvetrain noise THESE R ONLY THE COMMON FAILURES then there is the other parts leaking valve covers ,leaking fuel pump and constant starter cleanouts /rebuilds .

ABOVE all else diesels are reliable


grass disaster
07-11-2007, 05:16 PM
my zd18 diesel gets .6 gph

07-12-2007, 12:22 AM
hello, considering diesel against gaser
kohler gaser ,inlet maniflod vacumn leak, coil failure ,head gasket [s] ,valvetrain noise THESE R ONLY THE COMMON FAILURES then there is the other parts leaking valve covers ,leaking fuel pump and constant starter cleanouts /rebuilds .

ABOVE all else diesels are reliable


Just hit 550 hours on my 27 hp kohler. Not one problem with it. I know its still relatively new but the future looks good.

07-12-2007, 12:44 AM
hello , donot mis understand my post i actually do own kohler equipped machines . Kohler is an ok engine but they do have some obvious flaws . The positive is that they r commonly used and alot is known about them so there is huge experience with them .
The statement was more 4 general comparison ,a common gas engine against a kubota or a diahatsu diesel 4 eg

There is a truck company with the saying """reliability is everything ""
they only run diesels

As it is stated by some makers of mowers ,if u trade your mower every 2years or less buy a gaser if u keep your mower longer u should purchase a diesel . That was printed in a walker magazine .

Walkers statement is that u will go through 2--3 gasers for every diesel [engines that is ] This of course has down time while machine is having a new engine fitted

08-06-2007, 09:36 AM
Is it why Brickman seems to use gaser over diesel? Because they probably change every 2-3 years...?

KTO Enterprises
08-06-2007, 12:33 PM
You can also buy off road diesel for equipment which is even cheaper that road use diesel.

08-06-2007, 04:45 PM
My Z593D Toro consumes .7 GPH. Maybe .8 GPH in harsh conditions. I run off road diesel, Which is $2.35/gallon. Mower has a 23HP Kubota on it, and I've had very few times where I wanted more power. 99% of the time, she hums right along. I have yet to bury this machine, although it's been relatively dry this season. I would do it again for sure. I love this diesel. Although, the deck attachment system is another story.

08-06-2007, 05:30 PM
Is it why Brickman seems to use gaser over diesel? Because they probably change every 2-3 years...?

They change every 1 1/2 years. The buy them in the spring and then use them for 2 seasons and sell them in the fall.

08-06-2007, 06:28 PM
Maybe we can learn a lesson from them...For sure they are very big...but they probably calculated everything and its more profitable to change them every 2 years or less than keeping them as long as possible..but this could be in an other thread.

David Gretzmier
08-06-2007, 06:44 PM
I have tracked kubota diesels, 21 horse at .5-.6 gph, and have seen less when under less load and cutting the rpms back a bit. the 26 horse disel in the new 326 kubota my brother is using is around .7-.8, but again, less if you back it off a bit. my 19 horse kawasaki, brand new at 15 hours burned through 4 gallons in 3 hours, or 1.3 gph last week. I seriously doubt the 30 horse kohler uses the same amount of gas, but I am open to being wrong. most folks are reporting 2 gph on the larger gas engines.

08-06-2007, 09:44 PM
I was at my Toro dealer today asking him about buying new 72" zero turns for next season. He said the Toro, Exmark, and Scag reps have all told him that in all they have seen the digitally fuel injected and liquid cooled kawasaki machines are getting the same if not better fuel consumption that the kubota or diahatsu diesel. I know that my the rest of my machines will be worn out long before the diesel engine will be so I will probably save about $2000 a machine and go with 29 horse liquid cooled fuel injected kawasaki power.

08-13-2007, 12:56 PM
Gas vs. Diesel depends on you application and long term plan.

Pro's of diesel:
- more torque accross all RPM's and cutting speeds (just doesn't bog down)
- fewer oil changes (provided you use quality synthetic oil and filters)
- both Kubota and Cat diesels are rated to 5000 hours (conservative)
- lower full consumption compared to higher HP gas (30%)
- lower operating cost over life of engine (if they are properly maintained)

Con's of diesel:
- more expensive to purchase

Gas engines have their place and I use them too, but my Grasshopper 928D is hard to beat over the long term.