On the Harbor Freight 800 Watt Generator: Usage Tips and Helpful Modifications for the Moth Collector

Harbor Freight 800 Watt Generator

Harbor Freight 800 Watt Generator

I’m back into the Lepidoptera collection game this year.  After many years away, I decided that I was coming back to a hobby I’ve loved my whole life.  I particularly enjoy collecting the beautiful moths that we have in Utah, and I am putting together a white sheet collecting kit that consists of three mercury vapor lamps and two compact fluorescent black lights.

Night collecting at a white sheet is a tried and true method for gathering moths.  Using a set of Mercury Vapor bulbs will provide the correct wavelength of light to attract most species of nocturnal Lepidoptera.

Unless I am collecting in the back yard though, a portable power source is going to be necessary.  The Honda EU1000i is a very high quality, extremely quiet and reliable generator; its $700 cost was prohibitive for my purpose however. The little 800/900 watt Harbor Freight generator is often available for as little $89.00 and with a few modifications is perfect for the task at hand.  The full set of 5 lights will draw 520 watts of power.  That is only 65% of the capacity for the generator.  I really shouldn’t be taxing the generator at all.

After significant web research on the generator; I found that for it to be a truly dependable package, the HF generator requires a few modifications and a proper break-in period.  The following mods and procedures have been recommended by a number of users on various forums around the Internet and are what I used when I first bought the generator:

  • Replace the stock Chinese-made spark plug with an NGK (7832) BP5ES standard spark plug.  I keep a spare in my emergency parts kit that I carry in the Jeep while in the field.
  • While you have the spark plug out, give the cylinder a shot of STA-BIL fogging oil to provide initial lubrication to the cylinder/piston rings.  Replace the spark plug, but leave the wire off.  Now give the starter a couple of pulls to ensure the oil is coating the cylinder walls.  This helps to protect the cylinder during the first few seconds of running until enough oil has entered the system.
  • The original fuel inlet line is cheap rubber and often not correctly installed on the generator. Replace this hose to the carburetor with a good quality fuel line.  Also add an inline fuel filter for Briggs & Stratton engines, part no. 298090.  You’ll need two new clamps to add the filter in the line.  Make sure the line is fully seated and the hose clamps (now 4 with the inline filter) are securely fastened in the proper position (over the hose and barb).  I carry a spare filter in the emergency kit as well.  By the way, I know this is very old fashioned of me, but I much prefer worm-gear hose clamps over the squeeze type.  That’s just me.
  • Use a very high quality NMMA-TCW3 certified 2-cycle engine oil mixed at 50:1 ratio.
  • Although the manual states to run 89+ octane fuel, many users have found it best to run only 91+ octane gasoline.  I buy the highest grade available at the pump.
  • Add STA-BIL fuel stabilizer at a rate of ½ ounce per gallon of gas to protect against clogging and fouling while the generator/gasoline is being stored.
  • Follow the 25 hour break-in procedure in the manual to the letter.
  • Perform the recommended maintenance at the intervals stated in the manual.
  • When I store the generator over the winter, I start the generator, then turn off the fuel valve letting the generator run dry.  The STA-BIL in the tank will keep the fuel from fouling.  When the generator cools down, I remove the spark plug, and give it a shot of fogging oil.  Then replace the plug and give the starter a couple of pulls to distribute the oil.

My break-in consisted of running the generator for a total time of 25 hours over a period of 5 days, with a 500 watt halogen work light plugged in.  In order to track runtime for maintenance, I keep a run/maintenance log of when I run the generator, for how long, at what elevation and any maintenance I perform.

I’ve also purchased and now carry in my Jeep, a 12V battery charger should my vehicle batteries run down while out in the field, I can use it connected to the generator to charge them.


UPDATE:  I just ran across this little hour meter at www.motominder.com and will install it on
the generator for maintenance interval tracking.  At only 1″ X 1.5″ it will fit nicely on the unit and only requires an inductive coupling to the spark plug wire and a ground connection.  Should be just what the doctor ordered. I’ll let you know how it works.


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