You're asking about paralleling generators with different engine brands, specifically a Honda (GX series) and a Briggs & Stratton. It's a more challenging situation than paralleling identical generators. Here's a breakdown of the issues and potential solutions

The Core Problem: Different Governor Characteristics
Governor Response

The fundamental issue is the difference in how the governors on the Honda and Briggs & Stratton engines respond to load changes. Governors are designed to maintain a relatively constant engine speed (and therefore generator frequency) as the electrical load on the generator increases or decreases.

Hunting

If one governor is faster or more aggressive than the other, it will constantly try to "correct" the frequency, potentially leading to hunting (oscillating up and down in frequency). This can damage equipment and make the generators unstable.

Load Imbalance

Even without severe hunting, the governors might not share the load equally. One generator could be working much harder than the other, even though they are producing the same voltage. This can lead to overheating and premature failure of the over-stressed generator.

Phase Angle Differences

Even minute differences in the governor and engine characteristics can lead to phase angle differences. This is harder to detect with a simple light bulb synchronizer, but will cause significant circulating currents between the generators, increasing the stress on them.

Why It's More Difficult Than Paralleling Identical Generators

Identical generators are designed to work together. Their governors are tuned similarly. Even with identical generators, paralleling requires careful synchronization (matching voltage, frequency, and phase).

The "Light Bulb" Method and Its Limitations The incandescent light bulb method is a very basic method for determining phase synchronization. It works by connecting a light bulb across the AC outputs of the two generators. When the bulb is dark, the generators are in phase and you can theoretically close the switch to parallel them. Issue #1: Slow Response

It's not very precise. The light bulb reacts slowly to frequency differences.

Issue #2: No Load Sharing Adjustment

The light bulb method does nothing to help balance the load between the generators. It's only about getting them initially in sync.

Issue #3: Limited Information

It gives you no information about the reactive load sharing.

Issue #4: Not suitable for different governors

You would need to use a synchroscope, instead of the bulb method, and also, you may also need to consider reactive droop compesation with the two generators sharing load.

Is It Possible? Maybe, but with Caveats and Risks

It is possible, but likely to be challenging and may require modifications and/or monitoring.

Here's the best-case scenario


Small Generators, Light Load

If you're dealing with small generators (e.g., under 3 kW each) and plan to draw only a small load (e.g., a few hundred watts), the system might tolerate the governor differences. You'd still need to proceed carefully.2.

Close Frequency Matching

Aim for extremely close frequency matching before connecting the generators. Use a frequency meter (not just relying on the light bulb).3.

Monitor Carefully

After paralleling, constantly monitor the voltage, frequency, and (if possible) current of each generator. Look for any signs of hunting or load imbalance. Use an ammeter on each generator's output.4.

Be Ready to Disconnect

Be prepared to immediately disconnect the generators if you see problems.

Steps to Take (If You're Determined to Try)


Preparation



Review Generator Manuals

Thoroughly read the manuals for both generators, paying attention to any information about paralleling or governor adjustment.

Safety First

Ensure both generators are properly grounded. Use appropriate safety gear (eye protection, gloves).

Location

Perform the test in a well-ventilated area.2.

Synchronization (Assuming you're going with the light bulb method – VERY risky with different engines, see warning above)



Setup

Connect the incandescent light bulb between one leg (phase) of each generator's output. Make sure the voltage rating of the bulb is appropriate for the generator voltage.

Start Generators

Start both generators, but don't apply any load.

Adjust Speed

Carefully adjust the throttle on one of the generators (usually the Briggs & Stratton, as it might be harder to fine-tune) to make the light bulb flicker slowly. The slower the flicker, the closer the frequencies.

Synchronization

When the light bulb is completely dark (or very, very dim) for a moment, quickly close the switch to parallel the generators. This is the moment when the generators are in phase.3.

Load Application and Monitoring



Gradual Load

Apply a small electrical load (e.g., a 100-watt light bulb or a small appliance).

Monitor Voltage and Frequency

Watch the voltage and frequency of both generators closely. They should remain relatively stable.

Monitor Current

If you have ammeters, check the current output of each generator. The currents should be roughly proportional to their power ratings.

Listen for Unusual Noises

Listen for any unusual noises from the engines or generators.

Monitor Engine Temperature

Check the engine temperature of both generators. If one is running significantly hotter than the other, it's likely overloaded.4.

Troubleshooting (If You Encounter Problems)



Hunting

If you see hunting (frequency oscillation), try slightly adjusting the throttle on one of the generators.

Load Imbalance

If one generator is significantly overloaded, try adjusting the governor linkage on one of the generators. This is risky and can make things worse. It's best to avoid doing this unless you have a good understanding of governor operation.

Important Warnings and Considerations



Damage Risk

Paralleling generators with different engine types carries a risk of damage to the generators or connected equipment.

Governor Modification

Adjusting the governors is a complex task and can easily lead to instability or engine damage if done incorrectly. It's best left to a qualified technician.

Expert Advice

If you're not comfortable with electrical and mechanical troubleshooting, consult a qualified electrician or generator technician.

Automatic Synchronization

For reliable and safe paralleling, consider using an automatic synchronization and load-sharing controller. However, these controllers are typically expensive and designed for larger generators. They still might not work perfectly with significantly different engine/governor characteristics.

Reactive Power

If you are using inductive loads (e.g. motors), reactive power sharing will be an issue.

In conclusion, while theoretically possible, paralleling a Honda GX series generator with a Briggs & Stratton-powered generator using the simple light bulb method is highly discouraged due to the risks of damage and instability. If you absolutely must try it, proceed with extreme caution, monitor everything closely, and be prepared to disconnect immediately if you encounter problems. It's best to consult with a qualified technician or consider alternative solutions, such as using only one generator or investing in a generator designed for paralleling. Flag for review