As some know. I’ve been in micro power plants for 17 years for homes. I’ve also been involved in micro-cogeneration. We came up with some good designs and ideas. Unfortunately, the EPA came up with new tier regulations, and in 2006, this put the brakes on importing non tier certified engines. We were good for a while. At the time There were still plenty of small surplus industrial diesel engines available being sold for $500.00 to $700.00. They were sold cheap because they were no longer tier compliant to current EPA standards. In a nutshell, the APU manufacturers had to get rid of them. Unfortunately once they were sold, finding reasonable priced engines were slim.
Some non compliant models that were sold at a fraction of what they originally sold for:
Kubota EA300
Kubota Z482
Perkins 402C-05
Cat C.05
Yanmar 2TNV70
After retiring, power generation is still a hobby of mine.
I made some very nice 2 & 3 cylinder diesel gensets for fun. And sold them to fund my next project.
Years went by and in 2022 I decided to build my last one for myself.
In October of 2022 I saw an ad in Craigslist for a Kubota EB300 diesel engine. I was looking for one for about 10 years. These engines are outrageously expensive.
If you were able to find a Kubota EA330 at a Kubota dealer about 5 years ago they were about $4,000.00. Some dealers were selling them closer to $5,000.00.
The Kubota EA330 was the newer tier compliant engine that superseded the Kubota EA300. The internal differences of the engines were the EA330 bore was increased, the cold weather aid pump was removed, the hand crank start was removed. Different injection pump timing. This was all done to pass tier emissions. The EA300 & EA330 had the same output.
Now the Kubota EB300:
It was used by the military. It was mainly used on the Abrams Tank Carrier to operate the hydraulics on the trailer. What was so special about this engine?
• It was exempt from emissions.
• They were set up to run on Diesel and JP-8 fuel.
• Some were equipped with an SAE flywheel housing to directly mount a pump.
• They were much more flexible of an engine and could be set up to operate more equipment than the other models mentioned above.
Added:
Below are pictures of the engine when it arrived. I lost lots of sleep because I purchased it unseen from a person in California. I was wondering if I would be getting a $1,000.00 crate of rocks.
That was the riskiest Craigslist purchase I’ve ever made. Glad it worked out.
The Generator head:
Years ago I was able to become a Meccalte OEM licensed purchaser.
I was able to purchase a Meccalte SA20-130/2 for an unbelievable price. These are designed to operate 24/7. They are used to operate the controls and fans on trailer reefer units. The whole generator head is designed to handle road shock and vibration.
Rating is 10.5 kva
Set up to operate @ 120 volts only. There will be a switch to operate 120/240. But 120 load will be reduced.
Has momentary surge rating wired to 120 volts only is 87.5 amps.
With all the mass of the engine flywheel, pulleys and generator rotor. Heavy loads startup of compressors RV AC units and other equipment that need high momentary surge to start Is a breeze. All that’s heard it a blip from the exhaust.
Picture of the rating label:
Performance Curves
Note: The mil. spec’d EB300 engines are deliberately underrated on what they actually produce. The graph below shows a truer performance curve of what the EB300 actually produces.
The EB300 engine speed is set to 2657 RPM This brings the voltage frequency to 62 hz with no load. When the generator is loaded to 3,000 watts, frequency reads 60.3 hz.
First load test October 1, 2022
At 20 amps I believe the test numbers were 122 volts @ 20 amps. It equals 2440 watts. So a 2500 watt continuous rating for this generator seems good.
At 26 amps at 119 volts at 59.6 Hz equals 3094 watts. So I believe it's safe to safe to assume that 3000 watts is a good intermittent rating.
At 30 amps it safe to say that the little engine is overloaded. It gave a valiant effort but from its numbers 118 volts @ 30 amps equals 3540 watts. And that was a hard load to maintain. I let it make the load for 30 seconds before letting off.
So what it comes down to is that it's a great generator for 2500 watts continuous rating and 3000 watts intermittent rating. The length of run time for the intermittent rating has to be figured out.
The engine still is breaking in. It will be a while before I am able to figure out it’s true capability.
About surge starting capacity, there is no question that this generator will start the rooftop AC unit on the RV. What the total surge capacity is? I don't know. As I mentioned earlier, the generator had no problem starting a 1.5kw nail gun compressor with the air tank having 120 psi pressure during startup. It seemed like it did not know it was there. The brief surge current was over 50 amps. Some day there might be a time that we will find out.
Did not test fuel consumption yet. But I can mention that the numbers have to be good. We will find out later during spring or summer.
January 29, 2023
This afternoon I just did a fuel consumption test.
The fuel level was filled to a scribed line in the fuel tank filler neck. The engine was fired up and warmed up for 5 minutes then, load of exactly 3000 watts was ran for Exactly one hour. Once the hour was up, the power was cut and the engine was idled for 2 minutes and then shut down.
The fuel was replenished with a 100 ml measuring cylinder. The amount measured to refill the tank to the mark was 1152 ml. (just under 39 oz)
I'm very pleased with the fuel consumption.
She is a keeper.
February 21, 2025
Two years went by, last week, I was bored and decided to try something with the EB300 engine.
I was constantly thinking about retiming the engine because it seemed to have more fuel knock than I liked.
I started by backing the timing off 3 degrees. Did a loaded run up to 3,200 watts and there was a difference.
Here are the results of the test:
For reference:
0.1mm shim decreases the timing 1 degree.
In the Kubota manual It states timing was initially set 24 degrees BTDC.
I installed a 0.30mm shim. This brings the timing to 21 degrees BTDC.
• The engine starts the same when cold.
• idling during warmup is quieter.
• At full rated load at 2,600 RPM it is much quieter.
• The engine starts has no signs of smoke while idling or under full rated load.
The engine will be left alone and will be rechecked in warmer weather.
A spill-over test will be done to verify timing before going any further.
I'm thinking that 21 degrees BTDC might be the sweet spot @ 2,600 RPM.
Extra OEM shims on hand:
1—0.10mm
1—0.15mm
1—0.175mm
2—0.20mm
1—0.35mm
1—0.50mm
Was a very simple job.
What's also great is the way the fuel system is designed. It re-primes it itself very quickly.
The next day
Decided to do more testing.
After thinking things over during the night, I decided to back off the timing another two degrees. Did another spill test and timing is near 19.5 degrees BTDC.
The engine started up fine. The engine runs much quieter. Been running it for about 2 hours with a 2,880 watt load and it seems to be using less fuel. The engine seems to less stressed.
Update:
Doing another load test.
Right now the generator has been running a 3,240 watt load for 3 hours.
• AC frequency 60.3 hz.
• Outdoor temperature is 46 F.
• EGT is 514 F.
• Cylinder temperature 209 F.
• Radiator top. 197 F.
• Radiator is blocked about 85%
• Crankcase temperature.
Bottom 166 F.
Right access cover 172 F.
I originally spec'd the generator for 2,500 watt continuous load. Since the injection pump timing was backed off 5 degrees, I might be able to go up some. Possibly up to 3,000 watts.
Another test will be done in the summer to see if I'm willing to increase the rating.
2/23/2025 Fuel consumption test:
Did a 3,000 watt load test.
Here are the results
Fuel consumption per hour
920 ml.
31.11 ounces
0.97 quarts
0.243 gallons
The engine ran the 3,000 watt load before the test began. Every thing was monitored closely like before.
The fuel tank has a sight tube on one side and it was marked 3/4 of the way to the top.
Once the test started, there were no changes to anything. Once the test reached 59 minutes, 30 seconds. All electrical equipment was shut down and engine was allowed to idle for 20 seconds before shutting down. The tank was refilled with certified measuring cylinder marked in 1ml graduates.
This test confirms that the Kubota EB300 mil spec’d engine was originally set up to run optimally on JP-8 fuel. Backing the timing off just 5 degrees changed the performance of the engine considerably.
On January 2023 the engines economy was 1152 ml. (just under 39 oz) an hour. Today, 2/23/2025 After the injection pump timing was backed off 5 degrees, the engines economy is 920 ml. (31.11 oz.) an hour. That is a huge jump in efficiency for such a small diesel engine.
An engine that can run a 3,000 watt continuous load and use only 920 ml. of fuel is a very fuel efficient engine. A matter of fact many generator manufacturers can only dream of reaching such economy.
Three pictures of the assembled unit:
This one is a keeper and now in the next phase. Building a noise reducing enclosure.
Some good advice:
One of the reasons I posted this is to show how too much timing can hold back performance of an engine by too much additional combustion pressure the engine has to overcome by early ignition of the fuel. Diesel engines are much more tolerable than gas engines because the components are much heavier built to handle the additional stress. Most gasoline engines are not. This is why it’s so important to make sure cam and ignition timing is within spec. As we all know what happens to a gas engine when pre-ignition happens. If a member here has signs of detonation. Stop and fix the problem. Don’t keep running the vehicle.
Make sure the engine is set up properly to operate on the grade of fuel your using.
Oh…by the way.
For some enjoyment and some laughs, here are some links to videos that shows how tough the little Kubota E series engines are.
Check out the flywheels!!! “No Scatter Shield” If there is ever a flywheel explosion, someone could be cut to pieces.
Some non compliant models that were sold at a fraction of what they originally sold for:
Kubota EA300
Kubota Z482
Perkins 402C-05
Cat C.05
Yanmar 2TNV70
After retiring, power generation is still a hobby of mine.
I made some very nice 2 & 3 cylinder diesel gensets for fun. And sold them to fund my next project.
Years went by and in 2022 I decided to build my last one for myself.
In October of 2022 I saw an ad in Craigslist for a Kubota EB300 diesel engine. I was looking for one for about 10 years. These engines are outrageously expensive.
If you were able to find a Kubota EA330 at a Kubota dealer about 5 years ago they were about $4,000.00. Some dealers were selling them closer to $5,000.00.
The Kubota EA330 was the newer tier compliant engine that superseded the Kubota EA300. The internal differences of the engines were the EA330 bore was increased, the cold weather aid pump was removed, the hand crank start was removed. Different injection pump timing. This was all done to pass tier emissions. The EA300 & EA330 had the same output.
Now the Kubota EB300:
It was used by the military. It was mainly used on the Abrams Tank Carrier to operate the hydraulics on the trailer. What was so special about this engine?
• It was exempt from emissions.
• They were set up to run on Diesel and JP-8 fuel.
• Some were equipped with an SAE flywheel housing to directly mount a pump.
• They were much more flexible of an engine and could be set up to operate more equipment than the other models mentioned above.
Added:
Below are pictures of the engine when it arrived. I lost lots of sleep because I purchased it unseen from a person in California. I was wondering if I would be getting a $1,000.00 crate of rocks.
That was the riskiest Craigslist purchase I’ve ever made. Glad it worked out.
The Generator head:
Years ago I was able to become a Meccalte OEM licensed purchaser.
I was able to purchase a Meccalte SA20-130/2 for an unbelievable price. These are designed to operate 24/7. They are used to operate the controls and fans on trailer reefer units. The whole generator head is designed to handle road shock and vibration.
Rating is 10.5 kva
Set up to operate @ 120 volts only. There will be a switch to operate 120/240. But 120 load will be reduced.
Has momentary surge rating wired to 120 volts only is 87.5 amps.
With all the mass of the engine flywheel, pulleys and generator rotor. Heavy loads startup of compressors RV AC units and other equipment that need high momentary surge to start Is a breeze. All that’s heard it a blip from the exhaust.
Picture of the rating label:
Performance Curves
Note: The mil. spec’d EB300 engines are deliberately underrated on what they actually produce. The graph below shows a truer performance curve of what the EB300 actually produces.
The EB300 engine speed is set to 2657 RPM This brings the voltage frequency to 62 hz with no load. When the generator is loaded to 3,000 watts, frequency reads 60.3 hz.
First load test October 1, 2022
At 20 amps I believe the test numbers were 122 volts @ 20 amps. It equals 2440 watts. So a 2500 watt continuous rating for this generator seems good.
At 26 amps at 119 volts at 59.6 Hz equals 3094 watts. So I believe it's safe to safe to assume that 3000 watts is a good intermittent rating.
At 30 amps it safe to say that the little engine is overloaded. It gave a valiant effort but from its numbers 118 volts @ 30 amps equals 3540 watts. And that was a hard load to maintain. I let it make the load for 30 seconds before letting off.
So what it comes down to is that it's a great generator for 2500 watts continuous rating and 3000 watts intermittent rating. The length of run time for the intermittent rating has to be figured out.
The engine still is breaking in. It will be a while before I am able to figure out it’s true capability.
About surge starting capacity, there is no question that this generator will start the rooftop AC unit on the RV. What the total surge capacity is? I don't know. As I mentioned earlier, the generator had no problem starting a 1.5kw nail gun compressor with the air tank having 120 psi pressure during startup. It seemed like it did not know it was there. The brief surge current was over 50 amps. Some day there might be a time that we will find out.
Did not test fuel consumption yet. But I can mention that the numbers have to be good. We will find out later during spring or summer.
January 29, 2023
This afternoon I just did a fuel consumption test.
The fuel level was filled to a scribed line in the fuel tank filler neck. The engine was fired up and warmed up for 5 minutes then, load of exactly 3000 watts was ran for Exactly one hour. Once the hour was up, the power was cut and the engine was idled for 2 minutes and then shut down.
The fuel was replenished with a 100 ml measuring cylinder. The amount measured to refill the tank to the mark was 1152 ml. (just under 39 oz)
I'm very pleased with the fuel consumption.
She is a keeper.
February 21, 2025
Two years went by, last week, I was bored and decided to try something with the EB300 engine.
I was constantly thinking about retiming the engine because it seemed to have more fuel knock than I liked.
I started by backing the timing off 3 degrees. Did a loaded run up to 3,200 watts and there was a difference.
Here are the results of the test:
For reference:
0.1mm shim decreases the timing 1 degree.
In the Kubota manual It states timing was initially set 24 degrees BTDC.
I installed a 0.30mm shim. This brings the timing to 21 degrees BTDC.
• The engine starts the same when cold.
• idling during warmup is quieter.
• At full rated load at 2,600 RPM it is much quieter.
• The engine starts has no signs of smoke while idling or under full rated load.
The engine will be left alone and will be rechecked in warmer weather.
A spill-over test will be done to verify timing before going any further.
I'm thinking that 21 degrees BTDC might be the sweet spot @ 2,600 RPM.
Extra OEM shims on hand:
1—0.10mm
1—0.15mm
1—0.175mm
2—0.20mm
1—0.35mm
1—0.50mm
Was a very simple job.
What's also great is the way the fuel system is designed. It re-primes it itself very quickly.
The next day
Decided to do more testing.
After thinking things over during the night, I decided to back off the timing another two degrees. Did another spill test and timing is near 19.5 degrees BTDC.
The engine started up fine. The engine runs much quieter. Been running it for about 2 hours with a 2,880 watt load and it seems to be using less fuel. The engine seems to less stressed.
Update:
Doing another load test.
Right now the generator has been running a 3,240 watt load for 3 hours.
• AC frequency 60.3 hz.
• Outdoor temperature is 46 F.
• EGT is 514 F.
• Cylinder temperature 209 F.
• Radiator top. 197 F.
• Radiator is blocked about 85%
• Crankcase temperature.
Bottom 166 F.
Right access cover 172 F.
I originally spec'd the generator for 2,500 watt continuous load. Since the injection pump timing was backed off 5 degrees, I might be able to go up some. Possibly up to 3,000 watts.
Another test will be done in the summer to see if I'm willing to increase the rating.
2/23/2025 Fuel consumption test:
Did a 3,000 watt load test.
Here are the results
Fuel consumption per hour
920 ml.
31.11 ounces
0.97 quarts
0.243 gallons
The engine ran the 3,000 watt load before the test began. Every thing was monitored closely like before.
The fuel tank has a sight tube on one side and it was marked 3/4 of the way to the top.
Once the test started, there were no changes to anything. Once the test reached 59 minutes, 30 seconds. All electrical equipment was shut down and engine was allowed to idle for 20 seconds before shutting down. The tank was refilled with certified measuring cylinder marked in 1ml graduates.
This test confirms that the Kubota EB300 mil spec’d engine was originally set up to run optimally on JP-8 fuel. Backing the timing off just 5 degrees changed the performance of the engine considerably.
On January 2023 the engines economy was 1152 ml. (just under 39 oz) an hour. Today, 2/23/2025 After the injection pump timing was backed off 5 degrees, the engines economy is 920 ml. (31.11 oz.) an hour. That is a huge jump in efficiency for such a small diesel engine.
An engine that can run a 3,000 watt continuous load and use only 920 ml. of fuel is a very fuel efficient engine. A matter of fact many generator manufacturers can only dream of reaching such economy.
Three pictures of the assembled unit:
This one is a keeper and now in the next phase. Building a noise reducing enclosure.
Some good advice:
One of the reasons I posted this is to show how too much timing can hold back performance of an engine by too much additional combustion pressure the engine has to overcome by early ignition of the fuel. Diesel engines are much more tolerable than gas engines because the components are much heavier built to handle the additional stress. Most gasoline engines are not. This is why it’s so important to make sure cam and ignition timing is within spec. As we all know what happens to a gas engine when pre-ignition happens. If a member here has signs of detonation. Stop and fix the problem. Don’t keep running the vehicle.
Make sure the engine is set up properly to operate on the grade of fuel your using.
Oh…by the way.
For some enjoyment and some laughs, here are some links to videos that shows how tough the little Kubota E series engines are.
Check out the flywheels!!! “No Scatter Shield” If there is ever a flywheel explosion, someone could be cut to pieces.
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