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.

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