Unexpected problem with a "Simple" fix....or
not! Here is a discovery By Paul, AE5JU, that may help you
get out of the "Rough" with generator problems.
Almost two years ago, a few
months before becoming a ham, I bought a generator.
It is a PowerBoss by Briggs &
Stratton, with 13 HP Honda GX390 engine (390 cc), rated 7 kw
continuous, 12 kw starting, electric start, etc.
I would pull it out every month, run it
20 minutes or so, and put it back in the storeroom. It has, until
recently, run smoothly. Yes, I put in only enough fresh gas to run it a
bit, and ran it nearly dry each time. Then I would close off the fuel
valve and run it out.
I took it out to use for Field Day and it
ran rough. I had to pull the choke out a bit to get it to run smooth and
not "hunt", but it did run all day.
I took it to a nearby Honda
authorized service dealer, that sells and services Honda
generators and outboard motors, and a number of other generators and
outboards (Mercury, Suzuki, Yamaha, others).
The service dealer is
a trustworthy outfit and were well familiar with the problem. They
told me, and I was told the same by others, the problem I and others are
having is due to ethanol in the fuel.
Apparently the place where I get gas has recently changed to gas
containing ethanol and that was the cause of the rough
running problem. They also said the engine would run fine on pure
The upshot is to use a fuel stabilizer, and if possible,
use only real gas, not gas with ethanol. Steve K9ZW (a pilot) said
to use Avgas as it will have no ethanol if I can't find a gas station
selling straight gas.
Also, I need to run it more often and longer
when I do run it.
The final thing... they increased the midrange
jet by .001". The jet was not clogged, it was just too small for the fuel
obtained here. The ethanol leaning the mixture could be compensated for
with modern computer controlled engines but not with this generator. The
ethanol was just enough to lean it too far. Richening the midrange fixed
it. They still recommend using straight gas if I can get it.
the generator is working smoothly now, and I'll give it a better test run
tomorrow if it doesn't rain again.
I've also picked up some Stabil
(fuel stabilizer) and tomorrow will head out to the airport for some
Further research, we don't have a choice... "E10" (10%
Ethanol gasoline) is being forced on us. Pretty soon all gas
stations will have nothing but. Hope this helps you if your generator
starts to run in the "rough".
I've since picked up some Aviation
Gas. The guys at the airport said no fuel stabilizer was needed with
the Avgas, it will last for years. But I will use the Stabil with
pump gas with ethanol.
I ran the generator for 3 hours with the
ethanol containing gas (known as "E10", for 10% ethanol) I had used for
Field Day and the generator ran smoothly. After that had run dry, I
poured in a touch of the Aviation gas and ran through to flush out the
E10. I ran that until it ran dry.
Since the Honda
service guys modified the carburetor it is running smoothly on E10,
too. So, I'm ready for hurricane season now. 73 Paul -
Police, Fire, Rescue, Ham Radio, Aircraft, Ships, and much
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