3000W Chinese Gensets Info.

guy48065 wrote:
fter I bought my Wen "PowerPro 3500" way back in the early days of this thread I tested it under load and was impressed with the quality of its output even under full load. I keep it around if needed as an emergency generator and other than starting it occasionally it hasn't seen any use. Fast-forward to this past weekend when a storm takes out my power. Finally I get to use the generator. It starts right up and runs fine. I plug my fridge into it, fill the tank and head off to work. When I got home I immediately could tell it was running too fast. A quick check with my DMM verified the output was correct voltage but 78Hz frequency. To slow it down I had to back out the speed screw till it almost fell out. Then when I loaded it the engine lugged and frequency dropped to about 45Hz. Long story short (too late, I know...) the speed and load regulation on this genset now stinks. What could have happened in 10 hours use?

I never really gave it much thought before but just HOW does a generator maintain the output frequency at a steady 60Hz despite widely varying loads (and surges)? It looks to me to be the same spring & flywheel air paddle setup found on push mowers.

The WEN, like most all other 200 cc Chinese genny engines, are very similar to the Honda GX200.

It does not use the spring and air paddle governor system you may have seen on other engines.

The governor is internal and preadjusted when the engine is built. It runs off of the cam gear. You can get an eyeball here.

It is rare for the internal parts of the governor to malfunction - but it can happen.

Typically, one of the two springs on the external part of the governor assembly are out of wack or missing. They can also unintentionally entangle with wires or other loose items. The governor arm that reaches out over the flywheel can also come loose from the shaft that comes out of the engine.

The photo below shows the correct position of the rods, governor arm and springs. When the engine is off, the governor arm will have tension when pulled to the right. (The rust in the photo is from mouse pee. They made a home in the enclosure over the winter - time to clean and paint!)



Since your engine has been sitting, is it possible that some part of the assembly has gotten stuck? Run the engine and observe if the governor arm makes any attempt to move. This may give you some clues as to where to look next.

It is "tricky" to get everything back in sync if something is bent or broken.