Honda generator won't run under load

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  #1  
Old 05-04-15, 09:19 PM
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Honda generator won't run under load

I have a 10 year old honda generator EM5000x
Its at my cabin so I don't have the serial number handy.

I use it about every 1 - 2 months when we go up to the cabin for the weekend. Usually starts up right away on first pull.

This time started first pull as per usual.
I flipped the switch to 120/240, and also the large "projector" switch to on position.
I plugged in my septic pump, and it started to pump under load.
After about a minute, the generator all of a sudden started to cough and sputter and stalled.
I unplugged the load, turned off the switches and Re-started. Started right up again. Turned on the switches, no problem. Plugged in the load....sputtered and stalled.
Tried again a couple times and again would either stall right away or within 20 seconds.
Then I tried a different load just to see if the septic pump was the problem. I applied the cabin recharging load at 240 V. Same thing, sputtered, coughed and stalled.

Any ideas? do I have a short in the charging side?
 
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  #2  
Old 05-04-15, 09:42 PM
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Welcome to the forums.

I moved both of your threads to the gasoline powered forum.

I have a lot of those generators. They are excellent performers and are basically trouble free. I've never had an electrical problem with any of mine and I rent them out.

Do you leave the gas in the carburetor between uses ? If you don't shut off the gas valve and run the carb dry then you have a gunked up carb. It will need to be taken apart and cleaned. It is also very important to put a stabilizer in the fuel to keep it from becoming stale and gummy. I use Seafoam with excellent results. I have used Sta-Bil in the past but notice the gennys don't run as smooth with that in the tank.

When I have worked on other similar gennys for customers.... I'll usually pull the carb and send it out to a small engine repair center where they will soak the carb in a parts cleaner solution for maximum cleaning.
 
  #3  
Old 05-04-15, 09:51 PM
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Sorry for posting in the wrong spot.

The engine runs smooth enough each time I restart it.
It is only under heavy load that it stumbles. Its like someone jammed a big brake on.
 
  #4  
Old 05-04-15, 09:56 PM
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It's starving for gas. When you put a load on it the governor opens the throttle and you are not getting the fuel delivery you need fast enough.

There are a lot of little ports, channels and jets that get easily clogged especially with the current gas mixtures that are in use.
 
  #5  
Old 05-04-15, 09:56 PM
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Both of the ones at the one farm I do work at had this problem. Jets in the carb ended up being clogged.
 
  #6  
Old 05-05-15, 08:33 PM
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Ok thanks guys.
I don't understand but I'll take it apart and rebuild it. Maybe Honda's are different?
As I mentioned, I start it, its running under load for about a minute, so its getting the right amount of fuel, then all of a sudden it starts bucking and stalls...... did it just plug up the gas line?
And, when I restart it, why does it all of a sudden run correctly again, until I put on the load?

And yes, I do leave the gas in the carb between uses, I don't use any gas stabilizer in this one (I do use it on my 2strokes) and I haven't done any work on it for the last 5 years so its probably due.

I just rebuilt my 9.9 merc carb, my Yamaha 125 carb, so why not do the Honda as well??? cant hurt to try.
Any further info would help me understand why its doing this.
 
  #7  
Old 05-06-15, 05:16 AM
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As long as you are into the carb make sure the float and needle valve are working correctly and that there is a good flow of fuel to the carb. Check for a filter in the fuel tank and make sure it's not partially blocked and if you have an inline fuel filter I'd change it. A restricted fuel flow might cause the symptoms you describe. Fuel can flow fast enough to keep the bowl filled at idle and no load condition but it can't deliver fuel fast enough when the engine is under load so the fuel level in the bowl drops and the engine is starved.
 
  #8  
Old 05-06-15, 07:58 AM
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I've just finished repair on a power washer with the same problem(see Kohler power washer won't run off choke). Need to go through the carb thoroughly! Good luck!
 
  #9  
Old 05-06-15, 08:28 AM
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If that genny is like mine they use a combination fuel shut off valve/filter.

If you've kept the Honda supplied filter in the tank filler neck then your tank should be clean.
 
  #10  
Old 05-08-15, 09:41 PM
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OK, I'll give the carb a clean and scrub.....and report back.
 
  #11  
Old 05-10-15, 08:47 PM
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So this weekend I took the carb completely apart and gave it a good clean.
I left the throttle valve assembly and choke assembly installed as they don't have any internals.
Nothing looked really bad.
Cleaned out the fuel bowl, float level, and took out the jets and noted on the needle valve how many turns until completely "in" so I would know how to re-set it.
Squirted carb cleaner in everything and scrubbed it all up.
Blew out the jets with air, and put it all back together.
Fired right up, and ran steady.
Actually sounded like it ran a little smoother.

However, same as before, when I ran it for a while, I applied a large load (septic pump) and after a minute or two it coughed, sputtered and stalled.
I did the same thing just running it with the vacuum cleaner. After about 5 mins it stalled out.
Tried it with a small compressor..... worked fine, but thats a pretty small load.
If there is no load it seems to run fine.

I checked the spark plug and it looked good. If anything it looked like it was running a bit rich..... some black carbon deposits rather than totally clean.
I thought maybe it could be the oil sensor, so I checked the oil again... its right up to the correct level.
Could it be a faulty oil sensor?
Its almost like there is a fuel cut-off or electric cut-out.

can i bypass the oil sensor to try it out? Where is it located?
Anyone have any other ideas?
 
  #12  
Old 05-11-15, 04:54 AM
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I doubt it's the low oil sensor but it doesn't cost anything to disconnect it and see if the problem goes away. Look for the thing on the side of the case with a wire going to it. Here's one article that shows how the system works.
 
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Old 05-11-15, 01:29 PM
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I'll try disconnecting and see what happens.
Is there anything else that would cut of the fuel or the spark as described below?
 
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Old 05-11-15, 03:34 PM
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"as described below"? Was there supposed to be something below?

First, are you certain it is a fuel or spark problem?

The low oil sensor can kill the ignition as can the ignition switch or a broken or loose wire. If it's sorta reliably dying when the engine is good and hot but works after it's cooled then the coil could be going bad. The trick is to have the tools ready to check for spark and check as soon as the engine dies when hot. If you've still got spark then it's possibly not ignition related.

Does your engine have a solenoid on the bottom of the carburetor bowl?
 
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Old 05-11-15, 04:22 PM
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It is starting to sound to me as though it is not an engine problem but rather something on the gen side. Unfortunately I have not a lot of experience with the gen side without hands on and manuals from the manufacturer, (Not just owners manuals as they provide little for diagnosing problems of this sort)
It might be time to seek some support, as I recall the Honda website provided some good info for support.
 
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Old 05-11-15, 05:02 PM
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Try going to a welding supply shop or even lowes and get a set of torch tip cleaners. They are cheap. Run the biggest one that will fit up in the main jet in the carb. Sometimes a varnish buildup on the inside of that orifice can cause heavy load issue like this. The hole is big enough to supply the engine with the fuel it needs up to the point of full loaded throttle. It's hard to know what it's doing without being able to hear how it dies, but here's one thing that will help tell:

Look at the throttle lever on top of the carb. When the load is applied, does the lever go to 100% full throttle? Watch the throttle... while it is powering the load, does it ever drop away from 100% full throttle or does it stay there? Just before it dies, is it still at 100% throttle? If yes to all of these, it's either a fuel issue or load issue (either the engine isn't able to get all the fuel it needs to handle the load, or the load is too great for the engine). If the throttle is not pegged out during this time, then the problem is something else.
 
  #17  
Old 05-11-15, 10:08 PM
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as described below.... meaning what I had written in my post just previous....sorry for the mixup.
And yes it does have a solenoid on the bottom of the carb bowl.

I don't know if its fuel or spark problem.

It starts up fine, runs fine, then I apply load, still runs fine for a bit then all of a sudden it coughs, bucks and stalls. Starts right up again and runs fine till I apply load. I don't think it will show spark problem since it will reliably start again right away.


Next time I'm at the cabin.... hopefully this weekend. I will watch the throttle to see if its at 100% when it coughs.
thanks
 
  #18  
Old 05-12-15, 06:04 AM
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The solenoid on the bottom of the carburetor is to prevent backfire/afterfire. The solenoid blocks the fuel flow to the main high speed jet/circuit. When you turn off the engine it briefly continues to turn which draws in air & fuel even though the ignition has been turned off. This can cause an afterfire (many people call it a backfire). So, to prevent the annoying "pop" or "bang" when shutting down they use the solenoid to immediately cut off the flow of fuel to the high speed circuit. No fuel, no bang sound. The plunger in the center of the solenoid needs to move back and forth freely. If your's is gummed up or has debris preventing it from fully retracting it might??? partially block the fuel flow to the high speed jet. Maybe it's retracting partially and letting enough fuel by for the engine to run with a light load but not enough fuel when under heavy load.
 
  #19  
Old 05-12-15, 10:25 AM
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it moved easily with my finger when I tested it when rebuilding the carb.
I didn't know what it did though... thanks for the info as to function.
When I apply a significant load and it coughs it also backfires and spark/flame out the carb. Blows the filter out if I don't have the outer filter housing on.
 
  #20  
Old 05-12-15, 03:34 PM
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My boss bought the harbor freight gen the other day.. ( seems like a honda clone.)

Inverter Generator - 4.7HP, 2500W Inverter Generator



We just started it today. brand new out of box. Will not run a heat gun 1500 watts. will run a 500 watt drill fine.

When 1500 watt load is put on it overload light comes on..

Do you see this with yours>> Overload light?

I told my boss to return it and get another. Note it is very quiet.. I was impressed for $499 until it did that...

With that said I think his issue as well as yours may be voltage regulation..

We tested the hz. very stable under small load. but voltage drop was in the 90 v area.

With high load hz were stable but volts dropped to some 78 volts.. Seamed like it could not recover fast enough. Went into overload and stalled..

We tested with a meter that records voltage variations hi and low..

Something to look into..

Hope this helps...
 
  #21  
Old 06-01-15, 09:49 PM
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OK, an update.
So I bought the Honda Service manual for this generator.
First thing to check is the oil alert sensor.
I disconnected it and after about a minute, the generator did the same thing. Sputtered, coughed and dead stopped.
Then I restarted and while it was running, I shorted the oil alert wires. Went into a shutdown just like turning off the key, rpm dropped gradually till stopped.
So I believe i confirmed that the oil alert sensor works fine, and I think the problem is not electrical since shutting off the electrical gives a gradual stop as opposed to the buck/cough and dead stop that I am seeing.
I am also thinking that it under increased load and fuel that the problem occurs, but the gen function works fine before and after, so now I think most of you were right......its a fuel problem. Thanks for the advice, we will see how it pans out.

As a side note, I had two other small engines with bad gas - which now run fine, so I am now draining the 3/4 full tank, and next time I am up at the cabin I will make sure the lines are clean and will refill with fresh fuel and re-start.
Crossing my fingers.....
 
  #22  
Old 06-02-15, 05:41 AM
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Have you checked the valve clearances?

My pressure washer started sputtering and dying intermittently mostly though when it was good and hot. It gets used very intermittently so I thought fuel. Went through the carburetor and while there was some crud but not a lot and the problem persisted. I finally let it cool over night so I could check the valves cold. Sure enough both intake and exhaust were way too tight. I couldn't begin to get a .004 feeler gauge in so I don't know how tight but nowhere near the .006 intake and .008 specified for that engine. After adjusting the valves it ran perfectly for hours.
 
  #23  
Old 06-08-15, 10:33 PM
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Went to the cabin again this past weekend. cleaned out the gas lines, replaced the gas and tried it again.
Same thing. Ran for about a minute and a half, then what sounded like a missfire, maybe a couple times about 5 - 10 seconds apart, then coughed, bucked and stalled.
Started right up again...as it normally does...... but did the same thing over again after running about 20 seconds under load.

I guess its not gas, as it was new fresh stuff.

I'll try what Pilot Dane says and go check the valve clearances I guess.

Any other ideas??
 
  #24  
Old 08-08-15, 08:47 PM
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It was valve clearances

Last check I did was to see if it would run with the choke on. Left the choke on accidentally, and it didn't stall, even under load. Ran continuously with the choke on, so it just needed more gas.

I took it to Honda for the major service which includes carb rebuild and valves adjustment.
Now it runs fine.
thanks for the help.
 
  #25  
Old 09-10-15, 08:19 PM
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honda 3800x

I have the same problem and tried everything u tried . What valves have to be adjusted?
 
  #26  
Old 09-11-15, 09:37 AM
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The engine's valves. Intake and exhaust.
 
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