Switch 22hp gas to 18hp diesel, will it be less powerful?

[Superduper]

Got Craftsman garden tractor. Have had it over 10 years now. Probably worth close to nothing on used market. Tosses a few belts now and then but otherwise, has been working good after I did some reliability upgrades: changed the battery to optima (lawn tractor battery required annual replacement -- when they go dead, they are dead, dead), and replaced the original Carlisle turfs (go flat all the time) with Chevron Ag type tires (never lost any air).

Now the question. The engine is powerful and gets the job done but I've replaced the carb already and I'm spending too much time lately keeping it in top running condition. Being the tinkerer that I am, I'm looking to replace the 22hp Kohler engine with a 18.5hp Yanmar diesel. Do you think that even though the Yanmar is rated at lower HP, that it will perform satisfactorily in this tractor? The 29.5hp yanmar in my John Deere performs just fine but the machine outweighs the Craftsman by a factor of at least 5, maybe 6 times over. I'm guessing the Craftsman probably weighs in at 800lbs, 1000 tops with new heavier engine. There is no need to do any ground engaging work, the Deere handles all that. All I need it to do is scoot around and mow without bogging down. Parts are fairly cheap on these guys and design is super simple. What do y'all think?

 

[drtydeed]

Power would not be a problem for the smaller diesel. But they are a bit pricey.

 

[ray66v]

I would guess that switch will seem to have more power. Don't forget the added bonus, you will save money on fuel! Here is an example: I mow almost 4ac., gas mower uses aprox. 3 gal.fuel, diesel mower 1 gal. fuel. Get the picture. If you keep the mower long enough the additional cost of the diesel will be saved in fuel. And the diesel will out last gas engines by many hours.

 

[Superduper]

More power? Really? Nowadays, I don't see too many new garden tractors spec at less than 22 to 26 hp. My old Murray was an 18hp model but that one would bog down when grass was heavy. Of course these are all gas. I'm just wondering how much different it will feel being powered by diesel instead.

New diesel mowers are very expensive. I believe the lowest price diesel in John Deeres lineup is over $10k and I'm sure Kubota's is not far behind. My desire to make this swap is fueled mainly by desire for greater reliability. I'm tired of carb overhauls, starting fluid and just want something that keeps on ticking. I'm not expecting the quality of the mower to be that of a new machine and if I can keep it doing what it is currently doing, I've accomplished two things: (1) A working mower and (2) keeping another heap off my lot. As you know, these things aren't easy to get rid of when old and you can't just toss then into the trash.

 

[RonMar]

I think you will be more than pleasantly surprised. That craftsman gets that 22HP at 3600 RPM? The diesel will peak at about 1000 RPM less and be more comfortable to be around. My guess is that it will appear to do more work with less effort.

I have a 27HP craftsman, and a 28Hp diesel, and there is no comparison. One runs a 50" mower deck, the other runs a 5' brushhog and shreds 3" sapplings and brush without even breathing hard while the tractor and loader is pushing uphill thru brush that I can't walk thru...

As mentoned fuel is a big difference also. Both mine have 5 gallon tanks. One good afternoon mowing on the gasser and I have used 5 gallons. I can run the brushhog all day long at 2-3 gallons tops.

I run offroad diesel in mine and I have been paying less for that than regular unleaded gasoline.

 

[Soundguy]

My yanmar 1700 ran circles around my neighbors 26? hp gas rider lawnmower... drawbar pull.. mowing.. everything... whizzbang gassers get their hp rating in a factory test bench where they run top ful, special carb settings, no accessory loads, and rpm out of range of consumer use.. then they get the thing on the dyno, and whatever hp it produces right before exploding is what they write on the engine tag...

that tractor engine on the other hand.. will make it's rated hp all day every day, and when that lawnmower engine has been recycled into a toaster 3x over and sent to china, the tractor engine will still be making it's rated hp day in,day out.

soundguy

 

[Soundguy]

Hey.. if looking to go diesel on the cheap.. what about a chinese deisel for one of them jinma 185's or something?

soundguy

 

[BWBrown]

As mentioned above gas engines get their horse power at a rather high rpm - few of us actually run that fast, so we seldom see full horsepower.
Diesel engines are a different breed. They speak proudly of their torque - a more ralistic measurement of the ability to do real work - and at a rpm closer to what we are used to using.
The only time I actually have my (diesel) tractor rev'd up is when I need the PTO speed for a rear mower.
You will likely be pleased on several levels.
Bob

 

[Superduper]

Hey.. if looking to go diesel on the cheap.. what about a chinese deisel for one of them jinma 185's or something?

soundguy

Nah, part of the solution is salvaging something I already have and making it better. I already have an old retired Murray sitting in the weeds. I'd rather not have another lawn decoration. I noticed that the 18.5hp vertical shaft yanmars could be had complete for between $1200 to $1700. If I could plop that into the tractor, I figure it could mow all day long, day in, day out, and hopefully not have much problems except the occassional thrown belt, etc. These things are really simple, just a few pulleys here and there runs the whole shebang. Even the PTO is simply an electric "pulley type" PTO. I couldn't sell it for hardly anything anyhow and I figure investing $1,200 in a machine that I already know and have grown accustomed to using sounds a whole lot better than $12,000 for a new X748, even though I'm sure it's real nice.

As for replacing with a Chinese tractor, I believe I'll pass. I already have a nice John Deere that will do anything I need. Resurrecting the Craftsman is something that I want to do; a little of that Hod Rod younger years left over in me.

 

[Soundguy]

I didn't say replace it with a chinese tractor.. I said replace it with a engine from a chinese tractor.. probably half or a third of the cost of the yanmar engine... IE.. don't replace it with a 185.. but use the small diesel out of a 185.. etc..( or similar.. etc.. )

Soundguy

Nah, part of the solution is salvaging something I already have and making it better. I already have an old retired Murray sitting in the weeds. I'd rather not have another lawn decoration. I noticed that the 18.5hp vertical shaft yanmars could be had complete for between $1200 to $1700. If I could plop that into the tractor, I figure it could mow all day long, day in, day out, and hopefully not have much problems except the occassional thrown belt, etc. These things are really simple, just a few pulleys here and there runs the whole shebang. Even the PTO is simply an electric "pulley type" PTO. I couldn't sell it for hardly anything anyhow and I figure investing $1,200 in a machine that I already know and have grown accustomed to using sounds a whole lot better than $12,000 for a new X748, even though I'm sure it's real nice.

As for replacing with a Chinese tractor, I believe I'll pass. I already have a nice John Deere that will do anything I need. Resurrecting the Craftsman is something that I want to do; a little of that Hod Rod younger years left over in me.