# EU6500is: generator starts, surges; surging shuts generator down



## seanSL

Honda EU6500is Gasoline Generator is surging and will stop as this harmonic behavior feedsback on itself and stops the engine.
 


  Facts: starting the engine under load – in order to keep it from dying,24hrs of total usage, small quantity (tablespoon of “seafoam”) mixed in 2.5 gal of gas, engine operating under load (3100W) – so the engine is able to run and not have the engine stop because of the surge. 
  Assumptions: carburetor is clean (this seems to be a reasonable idea because the engine starts easily and runs smoothly but then after 3secs it starts the surging.
  Q: whats wrong & how do I fix my generator?


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## Robert Coats

seanSL said:


> Honda EU3000is Gasoline Generator is surging and will stop as this harmonic behavior feedsback on itself and stops the engine.
> 
> 
> 
> Facts: starting the engine under load – in order to keep it from dying,24hrs of total usage, small quantity (tablespoon of “seafoam”) mixed in 2.5 gal of gas, engine operating under load (3100W) – so the engine is able to run and not have the engine stop because of the surge.
> Assumptions: carburetor is clean (this seems to be a reasonable idea because the engine starts easily and runs smoothly but then after 3secs it starts the surging.
> Q: whats wrong & how do I fix my generator?


Title says "Honda EU6500is" but message says "Honda EU3000is" 

Which one do you have?


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## seanSL

sorry: it is a EU6500is


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## Robert Coats

One immediate and easy fix is to double-check the battery door service doors and make sure they are in place and secure. 

If the door is missing or not secure, too much air will be drawn into the cabinet and cause surging as the engine tries to correct/adjust the speed. 

Here's an article about it Honda sent to dealers:


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## KingDingy

How do these perform? as good as a standard generator?


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## Robert Coats

KingDingy said:


> How do these perform? as good as a standard generator?


They are really a premium piece of equipment. The inverter technology is very slick. 

A regular generator just turns an genset but must do so at exactly 3,600 rpm all the time to make 60 Hz power. So, you are burning a lot of fuel, and making a lot of noise, even if only a small load is connected.

Inverter models work different; first, the engine turns an alternator to make high voltage AC, then it is converted to DC, then finally inverted back to AC. This process means the engine can run at any speed necessary to make the correct power. Plug in a small load and the engine will barely move off idle. Plug in a bigger load, and the engine will speed up as needed. This means less fuel consumed, less noise, and more pure, "cleaner" power from the outlets. 

But they are not cheap. Inverter models from Honda run from $900~$5000 but have a 3-year warranty and really are considered the best portable generator available.


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## jmulvihill

I have been battling a surging problem with my Honda EU6500is for quite some time now. The unit always ran flawlessly, as I always made sure that I ran the gas out of the carb and drained the fuel when I was going to be storing it for a long period. That was great until about 2 years ago when my wife let someone borrow the unit during a power outage while I was out of town, and failed to tell me about it until about 2 months ago. That started to shed some light on the surging issue. Since Harvey hit down south of us, I decided to finally take the time to resolve it before I need the generator in an emergency, so started looking on many of these forums for suggestions/answers.

Issue:
EU6500is with about 82 hours of trouble free operation started to exhibit issues. First, I would start the unit with ECO-OFF, and it would run for about 5-8 seconds and would then shut down. Restart with no issue, then stop again in a similar timeframe. After the 3rd or 4th time restarting, it would start and continue to run, but would surge, even after letting it warm up. Flip to ECO-ON, and it would sputter really bad and sometime die.

I figured it was was a gas supply issue, so added some Seafoam (a fair amount stronger than the 2 oz/gal “normal” mix rate) to the fresh non-ethanol fuel I had filled it with. I let it run for about 30 minutes ECO-OFF to get fuel through the main jets, and also let it run for about the same amount of time with ECO-OFF hoping that the low speed jets would get some of the cleaner through them too. I then let the unit set for about 3-4 hours to soak. I started it up again, and repeated the process, but afterwards I let it set for 24 hours.

Upon restarting, the surging was still there with ECO-OFF, but the unit ran OK with ECO-ON and no load. When adding a load with ECO-ON, it would throttle up and again start to surge. Turning ECO-OFF with load, surging would actually get a bit better, but still hunting.

At this point, I went to these great forums to read up on what others had encountered. I saw numerous people who did carb work or even replacement with no fix. I then saw the battery cover explanation/resolution, but I had all of my covers closed. I decided to try some other things.

The unit does not really have a manual choke that I know of, but I found a way to improvise. I read that people were blocking the vents on the battery cover with paper to see if their seals might be bad, so I tried the same thing. Covering just the battery cover vents had no effect, so I decided to try blocking more of the vents on that same side, under the control panel area. I blocked maybe 85% of the air intake vents, and then the surging stopped. I assume what I had done was manually choking the air intake, making the air/fuel ratio change, meaning that it was definitely a fuel supply issue.

At this point, I dropped the bowl off the carb, removed the float, main jet and main nozzle and cleaned them all. The main nozzle did not just drop out, so I used a small hex wrench to jiggle it out. I let the main jet and nozzle soak, and got some large particles in the carb cleaner fluid. After letting it soak for about 30 minutes, I blew it out, and also squirted a good 5 second stream of carb cleaner up the float needle hole and up the main jet/nozzle hole. I reassembled the carb (actually twice as the first time I didn’t get the bowl back on correctly and had gas dripping out… oops), cranked up the motor and it is now running like new once again.

Anyway, I know that there is nothing magic about what I did. I am by no means an engine guru AT ALL. I just wanted to outline what I did, using all of this great data about what others have tried, in working to a resolution. Maybe this will help someone else to narrow down his or her problem. The only thing I tried that I had not seen from others was blocking more of the air intake vents to do the “manual choke” as I called it. NOTE: DO NOT USE THIS VENT BLOCKING AS A SUBSTITUTE FIX. I THINK RUNNING THE UNIT FOR MORE THAN JUST A FEW MINUTES WITH THESE VENTS CONSTRICTED WILL CAUSE THE UNIT TO OVERHEAT. Just use this to troubleshoot.

Good luck to you all! Have a great day!!


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