Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

Hi guys. I have tried getting to the root of this problem via other forums without luck.  After doing some searching, I was able to track down this forum, it's great!  I have a problem with my Honda EX350 generator. Here's some information regarding this unit in case you haven't seen one before. It is powered by a small two stroke engine mixed at a 100:1 ratio. The carburetor is mounted to the bottom of the crankcase and uses a single metal reed valve. The igniton is a solid state design. Because the generator is of an inverter design (much like the newer Honda generators), the engine does not have to run at 3600 rpm. There is a low rpm position (150 watts) and a high rpm position (300 watts). Here is the problem.

When in the high rpm position under full load (300 watts), after almost exactly 2 minutes of running, the thing bogs down for about 6-7 seconds (just like you were putting the choke on), then goes back up to normal rpm. This goes on until it runs out of gas, like clockwork, every two minutes. I cannot figure out what is causing this. I have checked absolutely everything and have come up with nothing. I have a friend who owns the same unit, and after spending hours troubleshooting my generator and finding nothing, I was forced to simply change parts to see if I could find the problem. Here is what was changed.

air filter, carburetor, reed valve, spark plug, exhaust, gas cap (vented)

None of this fixed the problem. The thing is, the engine starts first pull every time and runs at a steady rpm.  The engine just seems to be loading up and just bogs down for a few seconds, then it seems to clear itself up.

Here's the thing, partially blocking the air intake with my thumb causes the engine to run the exact same way until I remove my thumb. But when the engine experiences the problem by itself, it only happens every two minutes.

Does anyone have any ideas what might be the problem, I am out of ideas.

Bill,
Never seen one. No idea what I am talking about. Never stopped me before.
I'll guess tank over carb, no pump. I would still go down the fuel restriction trail. Hose, tank, filter, shut off valve, elbow, nipple.

does this happen only with a connected load? or with no load attached & anytime the gen. is running?

Thanks for the replies guys.  It only happens when running on high with the rated load, 300 watts.  I tried it again tonight, and it runs perfectly for 2 minutes, then it's like someone blocks the air intake, or turns the choke on. (I know for a fact that neither of those things is happening) This lasts for 5 seconds, then it clears right up, and runs perfectly for another 2 minutes.  If I run the generator with no load, it runs fine.  If I run it on low with the rated load (150 watts), it runs fine.  If I run the generator on high with 200-250 watts, it runs fine.   Only when I run the generator on high with the rated load (300 watts), does it act up.  I'm wondering if maybe it might be something in the generator system that's causing the engine to cut out under the rated load.

Thats what i was wondering & why i asked how it ran with no load. What kind of load are you putting on it?  it sounds like perhaps there is too much load on the generator, and overdrawing it would lug it down and make it act as you've indicated. 300 watts (2.5 amps, or 5 - 60 watt light bulbs) is a pretty small generator and would overload easily.. and its possible the generator head on yours is putting out slightly less FLA  than its rated at. you said a friend had the same generator, you might try his under the exact load and see how it behaves.

What sort of load requirements do you have for a generator? it may be to your advantage to go to a larger one, keeping in mind, tool motors for ecample require more start up amps than load running amps.

Thanks again for your help.  This generator was basically built by Honda to run lights.  That's all I run with it.  The 300 watt load is a spotlight that I run for ice fishing.  I have run the same exact light on other EX350's with no problem at all.  I'm lost at this point and don't know what to do.  I think I'll try switching inverter units with my friend to see what happens.  Any more suggestions are welcome.

I've never seen this model generator, but I'll venture a guess that the fuel tank way not be venting properly. At lesser loads, it gets enough fuel to run ok, but at high load, not enough air is getting in the tank allowing a partial vacuum to develop and just as the motor is starving for fuel, what ever is blocking the air flow in loosens up and lets air in for another 2 minute run. A total guess on my part, but easy enough to check out by loosening the cap and see how it runs.

  BJ,

I think you are right on the money, cap not venting!!

                                                                        Fred 

My bet would be something wrong with the inverter when running at full load.  There could be a capacitor or something within the inverter to help out when running at full load that is not working properly and draws down every two minutes, overloading the engine.

thats my thoughts, that for some reason its overdrawing the generator head. perhaps the output of that particular generator was a bit low, but within tolerance when manufactured. too.

i really think if it was a fuel venting problem, eventually it would fuel starve even at the low 150 watt setting, but an easy way to check this would be run it with the cap loose and see if the problem clears up.

also, if a volt meter is available, check the output voltage on the unit when this problem occurs, if it is only a matter of overdrawing the gen. head there should be a noticble voltage drop.

Wow!  Thanks for the great replies guys.  I really appreciate your taking the time to help out a stranger.  I have switched gas caps with my friend's EX350, no change.  Just for kicks, I'll run my EX350 with no gas cap, and let you know what happens.  When the generator "loads up" for a few seconds, the rpm's go way down and the overload light comes on.  This is normal as the ouput of the generator is dependant on engine rpm.  Higher rpm = higher output and vice-versa.  The 300 watt bulb does not seem to dim when the generator loads up, indicating a satisfactory voltage level..  I'll try the removing the gas cap for now.  I'll get back to you guys tonight...

 Bill,

Welcome to the Forum. There is a great  wealth  of Info here,  just hang on!

                                                         Fred      

Bill,

Check the spark plug and see if it gives any indication that it's over heating.  IIf the electrode is white, you'll know there is a problem.  If it looks good, then the inverter may be the problem.  Have you had a dealer look it over at all?

Same deal with the gas cap removed.  Spark plug looks great, golden brown.  I have brought it to a dealer, but they haven't been able to find anything either.   It's not their fault as this is a very odd problem.  Thanks again.

Just had a thought guys.  Is it possible the flywheel key could be slightly sheared?  Maybe not enough to make a significant difference under light or no load, but enough to get the engine to bog down after a few minutes of full load operation.  Then again, a sheared flywheel key usually affects operation regardless of load.  Just an idea...

I'm stumped.

Let me ask this.....when it bogs down, does it bog down to about the same point as when it runs in the low RPM mode?

in your origional posts you said "There is a low rpm position (150 watts) and a high rpm position (300 watts)" and that on the low wattage setting it runs fine. Have you tried connecting a lower wattage load, say 150 watts, with the generator set oh the high wattage setting? if the same problem exists on the high setting with a half load of 150 watts but on the low wattage setting things are fine, then that would indicate to me, its an internal problem in the gen. set itself. its very possible one of the components has a minute crack in the insulation (on the high wattage setting) and is opening up causing a leak or partial short to ground, causing the generator to create its own overload.

(i had this happen once on an electronic motor controller, the insulation on a current limiting resistor was cracked on the back side & as it warmed up the motor would cease to run, & what a b**** to find)

going back to basics though, double check your lamp(s) that you are not running more than 300 watts, a halogen work lamp for example, 300 and 500 watt lamps look identical. is it possible the bulb itself is a higher wattage than the gen. is rated at??

Hi Bill:

Well, here is my 2 cents worth.  Does this carburator have a mixture adjustment?  It kind of sounds to me that the unit is slightly out of wack and is acting up out of a bad setting.  Also, what about a governor?  Perhaps this might be slightly out of wack?

bbwb

spottedpony wrote:
Hmmm...  I believe I had previously posted that at the high setting with less than 300 watts load, the generator ran fine.  I was wrong.  I tested the generator on high with 3- 60W bulbs, and I got the same result, bogging at approx 2 minute intervals.  The odd thing is that with the 3- 60W bulbs, the bogging is not nearly as severe, but still there at the same intervals.  With the 300 watt load, the bogging is very severe. 

The bulb is definitely a 300 watt.  I have tried the same exact lamp on a different EX 350 with no problem whatsoever.

Man, I am about ready to throw this thing into the river...

It also sounds like your basic engine surge or hunting.  I don't know how easy it is to get to the governor linkage, but when it starts to surge or bog, see if you can hold the linkage steady to see if the engine smooths out.  If it still bogs or hunts, you may have a carb issue or the engine may have to be opened up and have the internal components of the governor checked.   

I'm thinking you have an electrical problem if it bogs down at the same regular interval with two different loads.  Hard to imagine a fuel related problem doing that.   Perhaps there's an electrical overload sensor that can shut down the ignition when it detects an overload.  This sensor could be defective.  You did say the overload light comes on when you have the problem.  Alternatively the electronic ignition module could have an intermittant failure.  Is the symptom the same if you push the shutdown switch for a second or so?   -Bob

It may seem im rambling a bit here but bear with me, some of this may shed a little more light on the subject, or at least get others thinking outside the box so to speak, for other solutions. Years ago, i built a small (12 volt) generator with a 3 or 3 1/2 hp briggs and a 60 amp alternator to use in our motor home for the times i didnt need to run the big onan gen. set.(man was that thing fuel hungry) My goal here was something small, but addiquate to keep the accessory batteries charged when we were somewhere 120/240 volt "household current" wasnt available. To make a long story short, it worked great, but on the first attempt with that alternator hooked to the engine you couldnt start ti, & the solution was to put a switch in the alternator field wire between the alt. and the voltage regulater to disconnect the load until the briggs was running, then it started fine & that little gen. worked like a champ, but you could sure tell when it was working hard, it would really make that litlte briggs work when a heavy charging load was put on it.

 after thinking about this, again,  im leaning  towards it being a faulty component in the gen head itself, or perhaps nothing more than a chaffed wire, that with vibration periodicly vibrates against the metal case causing an overload and pulling the motor down.

I would still do a voltage check on the generator when your problem occurs as this would be a good indication of the gen. being overloaded, & it might help track the problem down.& keep in mind, as voltage drops, wattage or amperage demands from an appliance increase. As a master electrician, ive delt many times with similar problems, due to overloading a panel or voltage from a transformer being low. Generally speaking, its acceptable to have +/- 10 percent of an optimal 120 volts.or anywhere from 108 to 132 volts when supplying lights or appliances however as previously mentioned, as volts drop, wattage demands increase, so its entirely possible that if the volt output of the gen. is low, by 10 percent, the wattage demand by your connected load has increased enough to effectively overload the generator.

im at a loss for any other thoiughts on the problem, but as discussed by several, im confident its a problem in the gen. head itself. Have you contacted honda directly to see what they're suggestions are?

I'm starting to think it's in the inverter unit also.  Honda doesn't want to hear about a model that has been discontinued for over five years, they'd rather talk about the current stuff.  I can't blame them.

Oh how I wish I could make some kind of recording so you guys could hear exactly what I mean.  It really is an odd problem that I have never seen on any engine of any type.

your lil engine is running lean...

needs a crankseal or possible cylinder gasket.

no big problem.

later chris

Chris, thanks for the suggestion.  Could you please elaborate?  Thanks.

you mentioned that you tried a few other fixes and nothing really worked.

when you partly close the choke it smoothes out a bit.

this leads us to beleive that there is a lean condition...not enough fuel in getting in the engine.

so either there is a fuel delevery problem ...you switched out carbs and checked that end,so its ok there.

or the extra air is coming from somewhere else...usually a crankseal.

on your genset ,i beleive that one side of your crankshaft goes into the gen side and the other side is where the start handle is.

i would check the easy side first.

later chris

Chris.
Can you find a vacuum leak on a two stroke like you would on a four stroke? Like spray some WD where you think the leak is while it is misbehaving and see if it makes a difference?

Hey Rob ...thats an excellent way to find the leak...

i usually use a little THICKER spray.wd40 dosent really have enough oil in it to stay around long.

i sometimes use a product called MOOVEIT,not sure if its available in your area.

any fluid that will burn in the crankcase should work pretty good.

you just spray it on and the engine will act a lot different when you find the seal or gasket problem

later chris

So Bill, was this mystery of yours finally solved?

I have also got the same problem, my friend gave me it and every were said it was 100:1 fuel mix when that is not correct it is 50:1 if you read on the filler cap and on the body of the geni, when i was told it was 100:1 i thought that aint alot of oil this could be why the machine is surging, my fist guess is the crank seal leaking air as it isnt being lubricated anuf

did you eva sort your problem out if you did what did you find?

Danno

Hi,

I am from the UK and have the  almost the same fault

I run the generator and when I first start it, green light is on then goes onto red overload and pulls the revs down

if you take the inverter cover off you might feel it hot in one place and you can also disconnect the blue socket

and just run it on 12v to try it you should see a diffrence.

I am sure you have nothing wrong with the engine but its worth checking the

float valve it could be trying to flood the carb but manages to keep going when its cleared.

if you happen to find any iverters for mine please let me know.

Les

Hi spacom.

Did you solve the problem with your EX350 ?

I recently ran across an ad on Craigslist for a used, inoperable EX350 for $100, so I bought it thinking that I could get it going relatively easily and at a reasonable cost.

Are there any special starting procedures for this machine??

The fellow I got it from said that he used it 2.5 years ago, placed it back in his shed where he stored it, ran across it last week when cleaning the shed and decided to sell, which is where I enter the picture.

The tank was empty, so I promptly filled with petrol with a 50:1 mixture. Attempted to start and nothing.

Removed the plug, and it appears to be brand new.

Checked for a spark, and there is none. Knowing that it is relatively rare for a coil pack just to "go out' from idly sitting in a shed, I am curious to know if I am missing something other than my mind.

Any and all help in this area would be tremendously and greatly appreciated.

Yours,
Jon