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Honda Gx390 Shutting down!

Discussion in 'Mechanic and Repair' started by Petr51488, Nov 24, 2011.

  1. Petr51488

    Petr51488 LawnSite Silver Member
    from NJ
    Messages: 2,377

    I've been reading into this problem and i see that it might be the low oil sensor and such. I did unplug the yellow wire and it still does the same thing. It starts. It runs for a little but when i start pushing the blower around, it shuts off. I keep starting it, it runs, and eventually it runs, but at that point i want to throw it off a cliff. I have no idea what it could be. The sensor is unplugged (the single yellow wire) but it still gives me problems. I ran carb cleaner through it for a while thinking it was something along those lines and it worked for the remainder of the day that i needed it (20 min) THe spark plug is new. Fuel is clean. Its been doing this pretty much all season. Any ideas??
  2. dutch1

    dutch1 LawnSite Silver Member
    from Jayhawk
    Messages: 2,249

    Running carb cleaner through a dirty carb will not necessarily remove the debris that may be partially blocking the main jet and emulsion tube.. Remove the carb. Clean the carb bowl, main jet and fuel nozzle/emulsion tube. You could have debris floating around in the bowl that is being picked up when the engine is running, then drops off when the engine is shut down. With the carb bowl removed, the main jet can be removed. The fuel nozzle/emulsion tube may fall out with the main jet or may have to be pushed out of the barrel of the carb from the venturi. Reach past the choke butterfly with a small flat screw driver to push it down. Even then it may need some persuasion.

    Here's a link to a typical carb on a 390.

  3. djagusch

    djagusch LawnSite Platinum Member
    from MN
    Messages: 4,350

    Besides cleaning the carb, replace the in tank filter, air filter, and gas line. I would guess all those parts would be under $25 and you are touching them all when taken off the carb. Clean the carb really well, take it all apart if you can, otherwise take it to the dealer (carb only) and ask them to clean it up.
  4. MowerMedic77

    MowerMedic77 LawnSite Bronze Member
    Messages: 1,164

    Have seen some of the newer large chrome emissions gas caps not venting try running loose and see if your issue continues...
    Posted via Mobile Device
  5. Petr51488

    Petr51488 LawnSite Silver Member
    from NJ
    Messages: 2,377

    Thanks for the advice. Just a few things to note. The engine runs fine for the most part when its standing still running full speed. But what good is a push blower when its standing still? It starts when its being pushed around. For some reason after i used a lot of carb cleaner ( and i understand about there still being stuff inside) it ran fine for the rest of the day (30 min or so left over). I ran it for 3 hours on one job and it only shut off once or twice and started back up, unlike the other times where it was constant pulling and using half choke etc. Another thing to keep in mind is that this, or any of my equipment does not get neglected. All fuel falves are shut off, stabil is used when putting away etc etc. I know problems can still occur when doing all that but just know that its not being put away in a sloppy manner then wonder why its not working when its suppose to. I've had nothing but great things to say about the 10+ honda engines that i own but this one is giving me some trouble and im sure its something stupid. I'll try what was suggested and will let you know.

    and i have heard of the venting issue. I'll take a cap off a different machine and replace it and see how that works. These larger honda's do have a different cap.
  6. EquipmentCity

    EquipmentCity LawnSite Member
    Messages: 3

    We replace several GX340 & GX 390 carbs, we order them from stens. For only $35 we just replace them instead of cleaning them. We have also had intermittent spark from a weak coil. You can do a simple OHM test to check the coil. Hope this helps.

    NEW CITY LAWN CARE LLC LawnSite Bronze Member
    Messages: 1,271


    Messages: 1,343

    We had the same problem it is the cap for gas.
    Posted via Mobile Device

    NEW CITY LAWN CARE LLC LawnSite Bronze Member
    Messages: 1,271

  10. Petr51488

    Petr51488 LawnSite Silver Member
    from NJ
    Messages: 2,377

    I'm not sure if it was the low oil sensor (it was unplugged before) but i changed the gas cap and it fixed it! Problem solved.

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