35hp Kohler gas vs. 37hp Kubota (fuel consumption vs. price)

SWS · August 25, 2024, 02:11:48 PM

I'm looking at a sawmill with power options of a 35hp Kohler gas or a 37hp Kubota diesel. Sawmill is fully hydraulic and will power all functions off the engine. 37hp diesel is about $10,000 USD more than the 35hp Kohler engine. I've heard the diesel is better on fuel but wondering how much better it is as I can't find any documentation on fuel consumption for either engine. Aside from resale value being higher with a Diesel engine and cutting being faster with the diesel, does anyone know what the fuel savings would be between the two? If it takes 50 years to recoup the fuel savings it may not be something worth it to me. If it only takes a few years for fuel savings to equal$10,000 then it would be a different story.

Thank you

doc henderson · August 25, 2024, 02:49:51 PM

I am not sure, but this is a good problem to think about. I generally feel the issues should relate to quality and would say buy the best you can afford. I think gas uses more gallons per hour as it may work harder, diesel uses less. gas is cheaper. The torque of the diesel will make it like two different mills. If you are going for production. the resale will not only be more for the diesel for the original cost, but the expectation that a diesel will last2 or 3 times longer than a gas engine. Not only sell for more, but prob. hold more original value than gas. If you are a hobby guy that has to run it past the CWO (chief wife officer) then gas may win the day.

all my thoughts are based on what I think I know

, not experience. I wish I would have gone diesel. to change it later, is more expensive and time consuming.

Nebraska · August 25, 2024, 05:56:50 PM

If the mill was used and 15 years old I would for sure buy a diesel. New I lean towards a diesel as well but all of the environmental junk they have added you will have to saw a lot to make up the difference. 10k$ still buys lot of gasoline.

SWS · August 25, 2024, 06:03:39 PM

Quote from: Nebraska on August 25, 2024, 05:56:50 PMIf the mill was used and 15 years old I would for sure buy a diesel. New I lean towards a diesel as well but all of the environmental junk they have added you will have to saw a lot to make up the difference. 10k$ still buys lot of gasoline.

I wonder how much of a power difference I'll notice between the two engines

SWS · August 25, 2024, 06:04:09 PM

Quote from: doc henderson on August 25, 2024, 02:49:51 PMI am not sure, but this is a good problem to think about. I generally feel the issues should relate to quality and would say buy the best you can afford. I think gas uses more gallons per hour as it may work harder, diesel uses less. gas is cheaper. The torque of the diesel will make it like two different mills. If you are going for production. the resale will not only be more for the diesel for the original cost, but the expectation that a diesel will last2 or 3 times longer than a gas engine. Not only sell for more, but prob. hold more original value than gas. If you are a hobby guy that has to run it past the CWO (chief wife officer) then gas may win the day. all my thoughts are based on what I think I know , not experience. I wish I would have gone diesel. to change it later, is more expensive and time consuming.

The CWO is watching my moves real closely haha

jpassardi · August 25, 2024, 07:29:59 PM

I think you'll be hard pressed to justify $10K in fuel difference. That would take a lot of hours. Torque, longevity and frequency of use are what I believe should be the driver to go diesel.
The only down sides to diesel are initial cost and any possible repair costs.
Good luck.

Percy · August 25, 2024, 07:45:08 PM

Ive owned 2 mills in my life. THe first one being a 35 hp wisconsin gas. I put 3000 hours on that one in 6 years. Then, 21 years ago, I bought another mill with a 42hp diesel(Kubota) which now has over 16000 hours. The daily fuel coniption of the diesel was/is half of the gas engine. My guzzintas(math) says im money ahead. Everyones scenario is different so a gas engine could make the most sense in some situations. My opinion would be if you are working fulltime milling, get a diesel, name brand preferrably. If you are hobby/part time milling, perhaps a gas makes more sense...sorta...heh.

SWS · August 25, 2024, 08:27:03 PM

I can hear you there. I"m not full-time Sawyer so it is tough to justify the expense. I"m out there a few days a week sawing though.

Larry · August 25, 2024, 08:52:20 PM

My mill came with a 34 HP gas Kohler. A few years later it got de-rated to I think 32 HP but close to your interest. I use a dragback and sticker stack hardwoods as I saw by myself most of the time. With normal 8' logs I'm ready to stack another board just as the saw finishes the cut. With 10' logs I have to wait on the saw to finish the cut. So, with 8' logs I have the optimum speed for me. More horsepower would not help production unless it could dragback faster or turn logs faster.

With a helper I'm way short on horsepower for maximum production, could probably make use of another 10 horsepower.

Here diesel is usually 30-40% more than gas. Of course if you want more paperwork you can get a tax break on off road use on either one. Lots of farm stations sell off road diesel without tax that will also keep the price down. I can't see the 10 grand difference unless I did lots more sawing.

Bruno of NH · August 25, 2024, 09:00:05 PM

Full-time Sawyer mostly some firewood days more for me keeping my sanity.
38hp gas Lt40 wide 3,300 ish hours
I burn 2.5 gallons a day on average.
I just see an lt 40 with a yarnmar diesel with 3,600 hourslisted for sale with the engine rebuilt already .
I'm happy with my gas engine so far , I'm in the minority with that on this forum.

SawyerTed · August 25, 2024, 09:57:48 PM

Hobbyist? Go with gas. Lower operating costs. Longevity probably isn't a big issue. Maintenance will cost less. Production isn't critical as much as quality lumber and quality time. Best bang for the buck when using "toy" money. Less pain and fewer financial regrets.

If you are looking for production, go with diesel - higher torque, better longevity and lower fuel consumption per unit sawed. If doing production sawing, 50-60 days of sawing will pay for the diesel. That's 2 1/2 to 3 months of sawing over the life of the engine which should be measured in years isn't much.

You can't measure the difference in fuel savings alone. Every time the mill has to shut down in a production setting costs money - just shutting down to refuel costs money.

Bruno of NH · August 26, 2024, 07:21:55 AM

My question is why the 37 hp yarnmar needed a rebuild at 3,600 hours ?

YellowHammer · August 26, 2024, 08:18:58 AM

I just looked up 38 hp Kohler gas engines in the web, quite a few offerings for new engines under $5K.

You could buy two brand new Kohlers replacements just for the cost of the diesel upgrade.

You said the mill had full engine driven hydraulics so I would want more power overall, whether it be gas or diesel, simply because the power feed will be robbing power during the cut. I've never run a sawmill that had too much power, I have run some that were anemic.

Do they have a higher hp model and if it costs less than $10K, I would upgrade the mill before I upgraded the engine.

SWS · August 26, 2024, 08:47:12 AM

This model I"m looking at has 35hp instead of the 38hp as they said that they had problems with the 38hp in the past so switched to 35hp. They don't have any higher horsepower models aside from this sawmill with the 37hp diesel option. I guess the reason question is whether I would notice the difference enough to make it feel like the $10,000 upgrade was worth it. Decisions decisions

YellowHammer · August 26, 2024, 10:06:40 AM

Can you take a test drive of each or either? How far is the dealer? I bet five minutes on the controls of each or either would answer the question. What does the dealer say? What brand is it and maybe someone here has experience with that model and engine?

Personally, we have weaned ourselves from all small gas engines, I just got tired of working on them the day they went out of warranty. I have diesels in everything from my vehicles, sawmill, tractors, construction equipment, even my 4 wheelers and lawnmowers are all "diesel" and they all "just run" with minimal maintenance. Most are Kubota or Yammer, the tractor has a Fiat, and I have never "lost an engine" in any, and our Kubota zero turn was 18 years old and run hard by me and my kids (Hey, go mow the farm", got overheated several times, ran dry of fuel several times, I can't tell you how many blade sets and tires, just generally abused and it was running as good the day we sold as new. Very impressive. Same thing with my Polaris diesel, on its 4rth set of tires, and still fires and runs perfectly.

I don't think a fuel savings will make up $10K, but I do think "other factors" would drive the decision.

doc henderson · August 26, 2024, 10:28:58 AM

The torque will keep up the RPMs and let you go through the wood at a steady faster pace. With gas you listen and when the governor kicks in and the motor pulls down a bit, that is as fast as you can go.

SWS · August 26, 2024, 05:16:37 PM

Quote from: doc henderson on August 26, 2024, 10:28:58 AMThe torque will keep up the RPMs and let you go through the wood at a steady faster pace. With gas you listen and when the governor kicks in and the motor pulls down a bit, that is as fast as you can go.

The torque alone would be a nice upgrade for cutting. I cut mostly 12" and under pine so I wonder if I'd recognize any cutting speed difference even with the diesel

doc henderson · August 26, 2024, 06:04:27 PM

I think side by side you would notice, but get what you need and can afford, and do not look back. Cheers! Doc.

dogbo2013 · August 30, 2024, 06:48:44 AM

I had the same question when I bought my LT40 and the opinions were all over the place. I went with the 38 HP gas. It wasn't until after getting the mill home and reading the manual that I got one of my questions answered. The manual rated the 38 HP Kohlers gas fuel consumption at 2-2.5 Gal/HR and the D35 Yanmar diesel at 0.75 Gal/HR. I can normally saw all say on less than 5 gal/day and I do not let my saw idle needlessly. I can not speak on the torque/power of the diesel, but so far I am happy with the 38 Kohler and have not had any issues.