YANMAR GENERATOR

[JLMTECH]

Hi, all,
I have would like to hear your thoughts about a used diesel generator I just purchased.
It has a 1985 Yanmar L40 diesel engine, air cooled, with a rope pull start, about 200cc
displacement and  4 horsepower at 3600 rpm. It drives a 4000 watt generator manufactured by
Dayton Electric Motor Co through a Lovejoy coupling. The engine and generator are mounted in
line on a 3 inch by 10 inch channel about 30 inches long. This steel hot rolled channel sits on a
one inch diameter tube frame with  two 10 inch balloon tires and a handle. It looks like a push
power lawn mower or a two wheel platform cart.

The whole thing weights about 300 pounds. I do not have a way to include a photograph.
 
The seller said this generator has been used very few hours. He backed up his pickup to the back
of my mini van and we heaved it into the back of the van. I almost dropped the thing, it is heavy.

I purchased it without starting it. When I got home one of my grown sons was waiting for me.
He has brought over his son to play with my younger children. He helped unload. I followed the
starting drill the seller described: Pull the recoil rope slowly to put the piston on compression.
This was easy to do since the piston would not go past compression. Then I pulled hard on the
starting rope and the whole machine came up on one wheel and slid around, all 300 pounds. My
son quickly grabbed the cart handle. I thought, this going to be painful. I better follow the proper
starting drill.

With the  piston on compression, I depressed the decompression lever and released it. Grabbed
the rope handle with both hands a pulled. Again the machine slid around on one wheel without
the piston going over compression. I missed something, I hope. Try again. I made sure the piston
was on compression. Depressed the decompression lever. It sprung back like last time. I know
that if I repeat the same exact procedure I will get the same exact results. Ba! So I pushed the
decompression lever again and it rotated  farther around. Ah, it caught and stayed in the rotated
position. I though, this is better. Again I gave the starting rope a hard pull with my son holding
the cart handle. Piston compression had vanished and the engine rolled over without doing the
one wheel act. When the piston came back on compression. It went puff, puff and picked up
speed. Life is great. The engine started one the first successful pull.

My son adjusted the rpm and I got two 1500 watt space heaters and plugged them into the
generator 110v  receptacles. The exhaust noise increased with each plug in. No back smoke, just
increase in exhaust noise.

The engine manual that came with the generator, lists four horse power max for the engine. I
have loaded 3000 watts and there seems to be room for a larger load. I  thought that two
horsepower is required for each Kilowatt.  I hope the fine people on this Form will make
comments.

The generator head has a cast iron round bell at the shaft end, a heavy metal band in the center
and stamped metal end bell at the other end. A sheet metal box is mounted on top with the 110v
and 230v plugins. The whole cart shakes a bit. The needle in the volt meter is missing.Vibration?
This generator has low run hours. The generator has three brushes. Voltage
regulation seems to built into the design. The manual says that voltage will vary less than seven
percent from no-load to full-load. Is this correct or am I missing something?

Questions: How long will the engine last?
         Will synthetic oil in the crank case increase engine life? By how much?
          Is there a panel volt meter that will not quickly lose its needle?
         What is the expected fuel efficiently, kilowatt hours per gallon?
          How can this generator get four kilowatts from four horsepower rated engine?
          Is a stationary mounting worth while?

I live in a hollow in north Alabama. We lose power a few time a year. Outages can last two or
three days. The longest ever was five days. In the past I have disconnected the grid power lines at
the main switch box and plugged in a 230 volt generator. This provides power to the whole house
and water well pump. The house usage rate averages about one kilowatt for lights, tv, freezer and
refrigerator.  The typical gas generator, 3600 rpm, uses a great amount of fuel. I hope this yanmar
engine will use much less fuel. How much fuel will I need for power outages.

Any comments on how the setup and or store this generator is very welcome.
Happy Spring, Larry

[Ronmar]

Should need 2HP/KW...  You were probably not at full RPM/frequency and not putting out full voltage, therfore the heaters did not draw their rated current and the generator was not under as much load as you thought it was.  Do you have access to a "Kill a watt".  IMO no one with a generator whould be without one.  A kill a watt will allow you to set the proper engine RPM for 60HZ and measure output voltage and load being drawn thru the device.  You can find them online, Harbor Freight sometimes carries them also.   

[JLMTECH]

Hi, Ronmar and All,

You are on the money. I checked the rpms with a killawatt. It measured 45 hz. I adjusted the
engine speed to 60 hz. The generator vibrations reduced. The two space heaters I am using for an
electrical load each have two settings 1500 watts and 1250 watts. With both heaters connected, I
can vary the generator load.  I found that at 2500 watts the exhaust is clean. At 2750 watts the
exhaust is slightly colored and at 3000 watt load the exhaust definitely has a black content. The
3000 watt load is probably too much. Not bad for this Yanmar 4 hp diesel engine at 3600 rpm.
Now I believe have a viable backup for electric power. Thanks Ronmar.

I would guesses from readers of this form as to the fuel usage per hour at a 1000 to 1500 watt
steady state load. This will give me a fuel storage quantity level for five days run time.

Thoughts on a permenent mount for the generator would be very welcome. Larry

[Ronmar]

I would guess somewhere in the neighborhood of 1/8 gallon per KW per hour...  Engine heat is a big factor in combustion efficiency, and air cooled engines do not regulate heat as well as liquid cooled engines do.  When it is cold out, they run cooler than when it is warm out.  Load also has more effect on their temperature.  Generally speaking warmer is better for combustion efficiency so you might burn more fuel on a winter day than a summer day for a given load..   You have a load, fuel and a watch right? You can confirm your particular consumption for yourself fairly easilly...

[glort]

I have 2 of these engines in this size and have run them on Veg oil for years. A Little petrol helps the power and I give them a good squirt when running from time to time down the intake with a plastic sprayer bottle.  Usualy do a whole Bottle ( litre) or 2 at a time.

Running veg I don't care what the consumption is, the fuel is free and the engines run on the stuff perfectly. The only thing I would suggest is don't leave the veg in the tank for long periods of non use as whatever the tanks are lined with and the way they are vented seems to make the oil Polermirise worse than I have ever come across with anything else.

In the end I ditched the metal tanks and just run the fuel from a plastic one with a disposeable filter in series.  Works well and I can have a much larger tank.

One of m,y engines did the pull starter so I just use a cheap electric drill with a socket on the end to start it now. Hold the decompression lever down with one hand while spinning it up with the drill with the other, let the decomp go and the engine takes off first time every time.

[JLMTECH]

Hi, Ronmar, Gloer, and All,

Thanks for the feed back.

With electrical loads at the one kwh level, a five day outage would require about 15 gallons of
diesel fuel, assuming eight kwh per gallon . Shutting the engine down for a few hours at bed
time would provide a big reserve.

Checking the actual fuel usage rate would be fun. I can connect the killawatt meter and a space
heater then run the engine for a measured time and measure fuel usage.

I am connected to the grid. I hope outages are limited so I do not run this engine enough to be
concerned about saving money using waste fuels.

The fuel tank has limited capacity, 2.5 liters. I want to increase its size. I am considering adding
a input tap a second tank, maybe a 5 gallon outboard motor tank. Would I have a  problem with
air bubbles in the fuel line? Any tricks to avoid air bubbles?
Larry

Reply

[Ronmar]

Where is your fuel filter located and what type is it?  That might be a good place to allow any possible air in the fuel stream to separate. An auxillary tank will need to be high enough to provide gravity flow.  A larger gauge T than the line diameter just before where it connects to the engine with the T pointing up and a line run back to the top of the tank would probably allow any air in the line to escape up.  There just needs to be enough head pressure in the fuel line to make sure the engine dosn't suck air back down the vent line.