Honda GX160 surging at all RPM's

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  #1  
Old 08-28-08, 03:54 PM
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Honda GX160 surging at all RPM's

I have a honda GX160 5.5hp motor on a pump and the motor keeps surging while running. I have soaked the carb overnight in the TYME brand carb soak and then reassembled, same problem but i noticed if i choke the carb about half way it will smooth out. So I'm wondering what could be causing my problem and how I go about checking it. Any help will be gratefully appreciated thank you.
 
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  #2  
Old 08-28-08, 04:46 PM
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A couple things come to mind, Did you replace the spark plug after soaking the carb ? A fouled plug could cause this, Also the spring on the throttle link rod if stretched/bent out of shape and engine high speed RPM's set above the 3600 range.


Good Luck
 
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Old 08-28-08, 04:53 PM
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A plugged or restricted pilot jet will cause this. Did you remove the pilot jet when you cleaned your carburetor?
 
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Old 08-28-08, 05:29 PM
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yes i pulled the jet, bowl, float and pin, crossflow above jet and soaked everything over night. since i had tried doing the same thing on three diff occasion with carb cleaner i dissassembled the carb each time on my bench and blew out everything although it didnt show any signs of dirt or clogging b4 i did that it was a safe and quick deal to rule out. i did not replace the spark plug i did the last time i worked on it 1 month ago but it has white deposits on it now (lean condition??) cant remember what it means. I havent messed with the linkage rods yet,i can slow the rpm down with the throttle and it doesnt matter if it is quarter,half,or full throttle it still surges i have had this problem for a couple months. the reason it is actually in the shop is the magneto would lose spark when hot.. the first time i think i put the wrong ignition coil on it. so it came back yesterday (1 month later) will only run half hr until hot
then if u let it cool and regain spark 5 min maybe. So i put a new ignition coil on it doesnt seem to shut down when hot yet but it still surges so I dont want to send it out of shop unless i can not figure it out.

I am going to run to a parts store and replace plug since it says the white is caused by overheating or wrong ignition timing. will see how it runs then.
 
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Old 08-28-08, 05:45 PM
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Ok i changed the plug. same thing surges unless i choke it half way. also it is in a utility box truck side compartment. when the door is closed and no choke it will smooth out also but i believe that is because it is not getting enough air so just like half choke condition. The main question is will the surging hurt the motor and will it be safe to give back to customer and let him start working with the pump again big weekend so he will need it.

Porta-Potty Pump truck that it is on.
 
  #6  
Old 08-28-08, 05:57 PM
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Possible air leak,did you change the carb. mounting gasket after you rebuilt the carb.

Jerry
 
  #7  
Old 08-28-08, 06:46 PM
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Did you check the pilot jet to make sure the small orifice was clear?

Did you replace the tiny O-Ring on the pilot jet?

Have you tired doing a static governor adjustment?
 
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Old 08-28-08, 06:49 PM
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Surging is a classic sign of a blocked idle or intermediate passage. Honda refers to surging as “unstable idle speed”. Your surging problem could have been further complicated during the soaking (immersion cleaning). Honda as well as most manufacturers does not recommend immersion cleaning.

Here is what I suggest:
If you have an Auto Zone parts store in your area pick up a can of “Valucraft Carb Cleaner” Part Number: AZ-4. I have been very successful in cleaning carburetors often without removing them from the engine. I have not had many carburetors I could not clean. Sometimes I use the entire can. At the price it sells for, so what.


WARNING - Do not get “Valucraft Carb Cleaner” in your eyes or on your skin. Use a full-face shield for eye and face protection. Wear protective gloves. The cleaner will damage rubber so remove rubber carburetor parts to prevent damage.


Valucraft Carb Cleaner will melt and wash away varnish. Spray as much cleaner as possible into the idle and intermediate passage. Follow by blowing out with compressed air. Be sure to blow passages and everything else out after cleaning.

Honda makes a set of jet cleaners for there carburetors. They sell for about $30.00 and are part number 07JPZ-001010B.

Honda carburetor check sheet:
http://www.honda-engines-eu.com/en/images/59138.pdf
 
  #9  
Old 08-29-08, 07:38 AM
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The GX160 runs great now thanks for all of your input. A different customer of mine had a 5.5hp honda look a like in my shop and I removed the carb from it and insected it, while looking at it I noticed it had an Air/idle mixture screw towards the intake side of carb. The one i was currently working on was missing that screw so i borrowed from one customers motor to get the other working and now it doesnt surge and runs great. Just another lesson learned but your input was very helpful and kept leading me in the right direction.

Thank You all,

Micah
 
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