The 3500 Super Quiet Inverter (item 56720) puts out 3,000 W continuously and up to 3,500 W for a few seconds when a motor starts. It runs up to 11 h at 25% load on a full 2.46 gal9.3 L tank. Noise is rated at 57 dB at 23 ft, 25% load. It takes 20 fl oz0.59 L of engine oil, and the source recommends SAE 10W-30. The spark plug is Torch F7RTC or equivalent, gap 0.027–0.031 in.
Specifications
Units: /| Power | |
|---|---|
| Running output | 3,000 W 1 |
| Starting output | 3,500 W 1 |
| Voltage | 120 V 1 |
| Inverter (clean power for electronics) | Yes 1 |
| Engine | |
| Displacement | 212 cc 1 |
| Fuel and run time | |
| Tank | 2.46 gal9.3 L 1 |
| Run time | 11 h 1at 25% load |
| Size and noise | |
| Noise | 57 dB 1at 23 ft, 25% load |
| Outlets | |
| Outlets | 2 × 120 V 20 A (5-20R) 1 × 120 V 30 A twist-lock (L5-30R) 1 × 12 V DC two-pin outlet (8 A) |
| Other | |
| CO shutdown | No CO sensor 1The later versions (items 71358 and 72899) add CO SECURE. |
Oil, spark plug and service
What to have on the bench before an oil change or tune-up.
| Oil capacity | 20 fl oz0.59 L 1 |
| Oil type | SAE 10W-30 1 |
| Spark plug | Torch F7RTC or equivalent, gap 0.027–0.031 in 1 |
| Change oil every | After the first 30 hours (break-in), then per the manual's schedule 1 |
Parts
Search links for common parts. Check the part number against the label on your unit before you buy.
| Part | Find it |
|---|---|
| Air filter | Amazon · eBay |
| Spark plug | Amazon · eBay |
| Carburetor | Amazon · eBay |
| Parallel kit | Amazon · eBay |
We may earn a small commission if you buy through these links. It doesn't change what we list. More.
Model numbers
This page covers model number 56720. Brands often sell the same name under several numbers with small differences, so check the label on the frame.
Compare
Often compared: Predator 3500 Super Quiet Inverter, Champion 201318 4500-Watt RV Ready Inverter, Honda EU3000iS, Generac iQ3500
Questions people ask
How much oil does the Predator 3500 Super Quiet Inverter (item 56720) take?
20 fl oz0.59 L. Oil type: SAE 10W-30. Oil change: After the first 30 hours (break-in), then per the manual's schedule.
What spark plug does the Predator 3500 Super Quiet Inverter (item 56720) use?
Torch F7RTC or equivalent, gap 0.027–0.031 in, according to the source. Check the plug in your unit before you buy a replacement.
How long does the Predator 3500 Super Quiet Inverter (item 56720) run on a tank?
11 h. That's at 25% load, according to the source. More load means less time.
How loud is the Predator 3500 Super Quiet Inverter (item 56720)?
57 dB. Measured at 23 ft, 25% load.
What's the difference between 3,000 W and 3,500 W?
3,000 W is what it can supply continuously. 3,500 W is a short burst for the moment a motor (a fridge, a pump, an AC unit) starts up.
Sources
- Harbor Freight owner's manual, item 56720 (UPC 193175417084). Owner's manual, accessed November 11, 2026.
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