Which Harbor Freight Generator?

The robot team has a meet this week in a UP city with a Harbor Freight. Do any of you have any recommendations for which generator to buy if they have them in stock?
I have cargo space for any size.


I have the 4375 watt model which is 3700 watt continuous. I chose this one because I believe it is the smallest one they offer with the 220 volt plug. That way it would run my welder and plasma if I ever needed it for that and it has a 16 hour run time at partial load. It starts with one pull and its quiet.


I would get one with 220, and it depends on what you want to do with it. @Matt is probably the expert on them. I think not only has he run through most of them, he has their whole catalog memorized. :stuck_out_tongue:

I snagged one off CL for backup, and the gas smelled gelled, but it got to be winter so I didn’t work on it. I don’t like working in an unheated area with gloves off. :stuck_out_tongue:


Yeah depends on what you want to do with it. i would not go any smaller than the 4370 212cc generator. This generator and anything above are good for woodgas. I have not tried the 9500 inverter yet. My 8750 Inverter generator Im happy with so far, it is a bit better on fuel than the old versions.

On wood gas the 8750 is good between 2500 and 3000 watts. The smaller one I have not ran in years I would guess 1500 watts should be doable but would not expect much more than that. But this smaller version does not have electric start so they are a no go for me. for wood gassing.

The older 8750 generators I think they are phasing out and have been selling them cheap so watch our for them.

The 9000 watt version has a flat top piston versus the 8750 has a dished piston. So that is the difference between them. Other than that they are the same generator.

You can rebuild them but you have to search and make sure you get the right parts as there was the hemi’s that are phased out and the pistons and rings are different on those versus the newer ones. The Predators are beast and Id take one over a Honda any day.


There is a sweet spot where you want to run a generator on gasoline.
Between 50% and 75%
There you will get your best economy and not over load the machine…


Thank you Wallace,
I took your advice and placed an ad in the Smokstak-verse, and today received four shiny new brush spring clips in the mail.

So, at present the trip to Escanaba’s Harbor Freight isn’t happening. I just get too tuckered out by 3pm to be much use to the robot team.
I do look forward to reviving the CCK.


Glad to hear!
It would have saddened me to hear that machine scrapped.

That really was one of the finest ones of its type
So robust they even made a diesel version


Interesting about the diesel conversion Wallace.
Converted to push rods, overhead valves?
Steve Unruh


It was called a DRP and they were made in the 50s.
Double the weight of a CCK.

Here is the manual for it.

This is NOT a DRP, but I cant find any pictures or running video of one.
This is a DSP and its sort of like comparing a CCK and a LK .


Thanks Wallace.
Yes. Converted to overheads valves.
Page 23, Fig 22 illustration shows the pushrod tubes.
Page 40 Valve Clearance Adjustments “remove cover panels on the cylinder heads” “rocker arms” “adjusting screws”. Shown at 6:25 in the video.
Ha! Pining Love is often what you cannot have. So truly then love what you can have.

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Its a nice engine but its no DJB.

J range engines are better and you can get parts and aftermarket support since they were manufactured into the 90s.

I believe when the the Studebaker corporation bought Onan they had a lot of tax credits given to them by the USgov. Onan needed money to build new products and some of this Sudebaker money was put into Onan to develop the J range.
Cummins never put anything into Onan, they just run it into the dirt and made the brand go away so they could focus on their product line up.

Anyhow advantages to engines that share as many parts as these J range engine:
If you want to build a real kick ass woodgas electric plant the J range has a bulletproof block and bottom end.
You cold easily put a turbo on a Ja or Jb and get the rated the power from it without any fear of stressing anything inside.

There are still a lot of MEP-3 Military generators ( a Version of the 4 cylinder DJC ) out there. Parts are confusing because the manual does not indicate what parts are the same and you Cummins dealer will not help you because he’s a prick…

JC are still common and lots come up for sale because of the lack of suport from Cummins for older products like this.

Just remember these are heavy and huge.

Antiques like the DRB are cool to play with but hard to repair.
A CCK is still in that sweet spot where you will have a good simple machine you can find parts for.

I believe you can get all the gaskets and pistons and rings for about a 125 bucks at a place like I save tractors for a CCK.

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You may have seen the little aqua genny I run on chargas. When I got it off CL the filler neck was ripped out of it and the fuel hose was dry rotted. Obviously hadn’t run for a long time. All I did was silver solder the filler neck back in and get a new fuel hose. I then put e85 in it, pulled it over a few times till I was convinced the fuel was right through it, and let it set for three days. Then it started right up. I never even took it apart. My experience is that ethanol cleans everything.


I need to make sure the tank and hoses don’t leak since the tank is plastic. But e85 works like a charm. :stuck_out_tongue:


All alcohols have excellent solvent properties, but they mix with water and are this mix is a real problem for aluminum alloys and lead solder joints because it promotes corrosion.

SeaFoam is a well known brand of fuel system cleaner and most of its cleaning action comes from a combination of Iso-alcohol and nahpthas.
This type of alcohol is less damaging to metals than Methanol and Ethanol.


I don’t really make a distinction between any of these.

You are buying something from China and its a copy of a Honda.
Who offers the best warranty and deal is the real deciding factor here.
Inverter units kind of scare me because Chinese electronics are unpredictable

Where will you get parts and service after sale?
Will you repair or replace?

If you decide to replace rather than repair then buy what ever is on sale.

If you chose repair look hard at the components and see if you can get parts.
This is an on the shelf item at Princess Auto ( Canada’s harbour fright )
If you bought a 6500 watt power fist or Champions this will likely fit when your brushes wear out.

Will your brushes wear out before your rings?
Can you buy rings is it a standard engine?
A standard 6500 watt generator probably has a GX340 clone engine in it and those rings are easy to get.

A 420cc Predator might not be so easy to find a set of rings for.

If you scrap it non of this is a consideration move onto a different machine.
Or maybe not if you buy one like it you can often salvage brushes and engine parts to fix the next one free of charge.

Some basic rules of thumb sizing a generator:
A gasoline generator with a GX200 family of engines in the 196 to 223 range is rated between 5 and 6 hp with a bit of reserve power…
You need about 2 hp of each 1000 watts of generator capacity.
So if you buy a unit rated at 4000 watt with a 212cc engine you should expect it to reliably and efficiently power you at 2500 watts with some extra power available to start a motor load…
It may be able to put out more than that for brief times but if you expect more of it you may kill it especially a new one. ( after a few hundred hours of run time a nicely worn in Clone set can deliver a bit more power without the fear of it seizing on you but don’t abuse a new one )

This guy really wanted to prove his BFA was better than the Chinese set.
And it is…
But if the Champion had been broken in and adjusted as well as cared for I think it might have been able to run 24 hours at 2500 watts.
But its new the machining is probably not perfect, valves may have need adjustment.
This was not a fair test unless you plan to do ZERO maintenance to your set.

But I still want you to watch and think about it.
A brand new generator could not run 24 hours out of the box at its rated output.


Now I am going to add some more thoughts.

This is KOSHIN GEH4500 and it is not a Chinese unit and it is not at all like others.

Here’s a nice American brand name we all know on a Nice Chinese set as we would expect.

The Koshin has a big block 270 cc engine and MecAlt brushless ( and brainless ) head
The Westinhouse is a Small block 212 with a Brush type AVR head of Chinese manufacture

One made of Japanese and Italian parts ( probably sourced from a Chinese factory )
Other is an American branded clone of a Jap unit made in China UNDER CONTRACT ( lowest bidder of course )

The Koshin is the better unit while still being fairly inexpensive.
The parts are less stressed so its likely it can carry 4000 watts.

Crap shoot

Understand what it is your buying and what it is you want before you spend your money.

I would still look for a CCK-4 a BG BF type used thats been well cared for if this was for a long term use stationary applications.

But I want to show you this…

Its gold so made between 1965 and lets say 1985.
A K 181 EP engine ( 18 cubic inch )
It will put out 3000 watts, its only rating is 3000 watts and it will deliver.
it will even deliver than on propane or natural gas.


Look familiar?

Re-powered with a high compression big block Honda.

Your Mileage may vary…
That’s the engine off a Koshin GEH 4000 heavily modified to fit the 3000 watt Kohler head to ensure it could pull 3000 watts on Low cal NG gas.

The fuel also dictates what the gen can produce even if your burning those Dinosaur squeezings.

GX240 240cc rated at about 7 hp compared to the 18 cubic inch K181 rated at about 8
The 3-rm21 generator was designed to put out its rated power on any commonly available fuel.



Anybody know anything about this?
I still have it and it still rolls over.

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I think this are the folks. It looks like an induction motor so it probably isn’t self-exciting.



And this guy…it’s handy, runs the electric chainsaw. I had airplane oil in it and couldn’t start it by hand this winter.


The generator is a good one.
Here is a regulator you can adapt to it.
Man where do you find this stuff!!!

Wisconsin runs good!
Thats a keeper.
Long rod long stroke low compression engine will burn any grade of fuel.
Aeroshell 100 is great oil.
If you go back over my posts over the years I bring that oil up now and then.
Its excellent stuff to store and engine.
Table spoon into the spark plugs.
Mix some into some Coleman fuel and squirt it into carbs and ports… all over engines as a rust inhibiting storage oil.
Use it as assembly oil.

Top oil mixed into your gas to protect an engine before and after wood gas use if you are afraid of moister.
That oil is designed to burn clean and not gum things so its excellent storage oil.