September 14, 2025 – The ExhaustNotes Blog

By Joe Gresh

My nesting work here at the ranch is taking me further away from electrical power. A 100-foot extension cord isn’t cutting it anymore. The little Harbor Freight Tailgator has been a trooper, but 700-watts isn’t enough for the electric jackhammer or two concrete mixers at once, and besides that the urge to spend money is strong.

Lots of buttons and outlets on the 4000. A 12-volt cigarette lighter outlet is unusual for cheap stuff.

A cool little fuel gauge is fitted to the top of the tank.

Rated 3200 continuous and 4000 surge, the ‘Zhen seems to power most anything up to 26 amps. That’s four times as much as the Tailgator.

The 30-amp, RV-type plug is great for welding.

But you’ll need an adaptor to plug your light duty flux core into the 4000.

This handy float bowl drain is a must-have for today’s crappy, alcohol laced fuel. Drain it after every use.

I’d like to see a little more weld on the frame. It would only take 30 seconds.

The inverter lives under the fuel tank. This is where the magic happens converting DC into AC.

Unlike a normal genset that hangs the AC portion off of the crankshaft opposite the pull start, the Shenzhen incorporates the power source inside the blower area and the rope start.

The generator came complete with a cute tool kit. You won’t get far with it but the thought counts.

The muffler isn’t super quiet like a Honda but it costs a lot less. The ShenZhen is around 63 decibels using my seat of the ear dyno.

I have more than the usual number of generators: in addition to the Tailgator, there’s a 10,000-watt Italian-Honda mash up and a 9,000-watt Predator (also from Harbor Freight), but both of those machines are heavy and hard to move on the steep and rocky New Mexico terrain we are currently beating into submission.

I wanted something light-ish that I could toss in a truck or carry downhill to a terracing job. It needed to have enough juice to run my equipment loads and if it could power the flux-core welder, that would be ideal.

At 60 pounds the Shenzhen 4000 seemed like the way to go. Amazon reviews on the generator were mostly good.

The ‘Zhen 4000 is an inverter-type generator. Unlike a standard AC generator which must run at a steady RPM to make 60 cycles per second, an inverter generator makes DC power (zero cycles or one endless cycle, depending on how you look at it). That DC is then converted to AC by an inverter.

The advantages to inverter-type generators are several:

1. The engine RPM can vary according to load making the unit more economical for powering lighter loads. At full load there probably isn’t much difference.
2. The frequency can be tightly controlled, putting out 60 hz regardless of the load.
3. The sine wave form can be cleaner with less noise. Small generators induce jagged wave forms due to the slight increase/decrease in crankshaft rotation speed through the engines power cycle.
4. There’s less noise at lighter loads, because the engine speed can be slowed to meet demand.

The disadvantage to inverter-type generators is basically a more complicated generator with more parts to fail. There is a slight efficiency loss converting DC to AC voltage but it’s kind of a wash (see Item 1 above)

The Shenzhen I bought from Amazon was $299. Now that I’ve bought it, my ever-alert Facebook algorithm is sending fly-by-night offers for the same unit at $149. If you can get it for that price without being scammed, it’s a hell of a deal. $299 isn’t bad either.

The choke was labeled backwards which led to a lot of rope pulling. It might be ok in the southern hemisphere but around here we peel the sticker off and flip It over.

The unit started right up once I realized the choke was labeled backwards and seems to have plenty of power. It runs my little flux core welder better than a regular receptacle. I’m mobile!

Time will mention under its breath if the ‘Zhen holds up and I’ll be sure to let you know if it’s junk. For now, it’s the real deal.