How To Adjust The RPM On A Honda GX390 Generator Engine

In this video I show you how to adjust the engine speed (RPM) on a Honda GX390 generator engine. Usually 3600 RPM is a good engine speed for your generator.
Always check with your manufacturer for correct engine RPM setting.

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[donyboy]

There is a link in the description to where I bought the tach in this video

[ctbcubed]

You can also plug a frequency meter into one of the power outlets and adjust the engine speed for a reading of 60 hertz (USA line frequency 60 cycles/ second = 3600 cycles/ minute hence 3600 engine RPM). Some generators have a frequency meter built in or you can use a device like a P3International Kil-A-Watt available from many sources. I like to adjust my generator for 60 Hz while the generator is supplying about a 50% load. As the load increases, the frequency will decrease a bit as the engine slows down and as the load lightens, the frequency will increase. My generator does not have closed loop frequency control, so setting the line frequency (engine speed) with a typical load is a reasonable compromise.

[kravenofspider]

Thanks for the info on the Tach. Have a great weekend Don.

[Jatt_Paji]

I have a Honda gx390 motor with a comet zwd4040 4000 psi pump on it. When I pull the pressure wand trigger, the rpm is normal, but when I let go of the trigger the rpm goes way up. What do you think I should do? Will the rpm screw work on the pressure washer?

[Tommyr]

I can watch this stuff all day! Another great video!

[charleshendrick]

Just a quick thank you young man for such clear vids and easy directions. Effectively have my generators purring like kittens. It seems regardless the issue, you have a vid with the fix, , , , saving me time and $$. Keep it up.

[alexsbikesandmotors]

shouldn't you set rpms when the engine is under load? Or does it make no difference?

[thewibb]

For those performing this you will want to check this under load as well. I like to use a 1500W heater as load and adjust accordingly. That way you know you frequency and voltage are in line under load.

[robertg]

I have a gx240 with the same configuration and with new carburetor only runs on choke and is surging, when spray ether by vacuum plate it runs correctly is it possible vacuum plate is bad ?

[ArdentImages]

Looks like it was 9 years ago but thank you so much for doing this! Really helped on a similar generator I bought 12 years ago :)

[marknye.thefixitguy]

How about a Honda EU3000IS inverter generator that rhe rpms are too low.
..how is that adjusted?

[vinnieromano]

Can I use a multimeter that measures Hertz instead.

[dj]

Great tip. Thank you. Could you show or tell me how you would adjust a the rpm's on a honda EU6500IS inverter generator. And what the rpm's should be at with Eco off snd on.

[richiem]

You have any idea what your Idle control ON RPM's are or what they typically should be? I have an old Campbel-Hausfeld GN654800AC with a GX390 and I can't find a manual for it or settings.

It runs fine and outputs 60hz @ 120V @ 3600RPM, I just want to make sure the Idle control RPM's are at a typical range (i think it was 2660RPM when ON). The idle control has a magnetic coil that can be adjusted around a bit to effect those RPM's. Adjust it too much and it will start revving up over and over.

[basspig]

I just got a 6000W sungold power inverter that I intended to use as overnight backup to my Honda Northstar brushless generator, but it refuses to qualify the generator power and switch the input side to the output. It instead remains on battery inverter mode and the status display says "AC ABNORMAL 238V" on the input side. The generator frequency is 62Hz. My APC UPSes don't have a problem with it, but the sungold absolutely refuses to qualify it.
I'm going to try adjusting the engine speed, but I fear that under load it will drop below 60Hz and the inverter will go to battery again.

[cayrick]

Have a Honda hour meter tach on my EM5000 generator with a propane kit. The propane connects to the intake line pre carb and I measure 3640-3680. line freq = approx 57 hz. Given that I am running propane and I have tweaked the propane delivery valve to produce the highest RPM will your carb adjustment work?

[mocoffeejake]

Thank you, this was exactly the information I needed and very clearly presented.

[charleshendrick]

I have about the same generator and adjust engine speed with it under load, , a couple 500 watt halogen lights work well for this. Bought one of those 20 buck tach/time gauges ...simple surface mount... makes keepin up with 60 hz easy and hours on motor for oil changes

[RedRoyce]

Thanks great video. I needed to clean carb but seen they were cheep so I just replaced it. It started easy but the RPMs are way to fast now. Looks like the gov linkage isn't moving over to slow it down unless I hold it over by hand. Is this what I should adjust for this or do I need to look into the gov?? Thanks It worked fine the last time I ran it.

[harperjmichael]

Just a note to add, 3600 = 60 Revolutions per second which is where 60Hz frequency comes from for your power. If you have more or less RPM your power output frequency will be more or less. Europe uses 50Hz and the US uses 60Hz. I'm sure other Countries us some variation of the two as well because appliances are designed for either, or, or both.