QuestionQUESTION: Hello John,
I have a 1986 Honda ES6500 2 cylinder water cooled generator that for no apparent reason has decided to start pushing a measured 5 psi worth of pressure out the port on the plastic vacuum plate between the carb and intake manifold. As you can imagine this is raising cane with the governor operation. I have checked compression at 140-150 psi on both cylinders. It starts and idles perfectly but when you throw the engine speed switch from Auto to Run it pecks and hunts and never finds 3600 rpm. I have installed a new carburetor and a new vacuum control valve for the low speed servo.
I can not explain 5 psi pressure where there should clearly be vacuum. Other than this pressure and subsequent erratic behavior it runs like a top.
Your thoughts are very much appreciated.
Thank you,
Dennis Waters
ANSWER: Hello Dennis:
Are you Sure the Vacuum Hose is Going to the Intake Manifold and Not to the Crankcase Breather? You can View a Breakdown/IPL of the Mower/Engine at this Site Addy, http://hayward.arinet.com/scripts/EmpartISAPI.dll?MF&app=ASP&lang=EN&TF=Mainfram and Select the Catalog American Honda. Select the "Generator" File. Scroll to your Unit and Click on it. Now Select the "Cylinder Barrel" File. The Crankcase Breather is #s 7, 8, 11 and 28. If the Crankcase Breather is Dirty, then it will Allow Crankcase Pressure (Normally 5 psi) to be Pushed Into the Carburetor and Cause the Problem you Described. On Some of these Engines, there is a Check Valve in the Plastic Insulator you Described. It May be Stuck and Requires Cleaning or Replacing. Send me the Complete Model Numbers Using the Site Addy I Provided, please. With these I can Locate the Proper Breakdown and Better Assist you. Thanks.
Respectfully
John
PS: I am Allowed to Answer 10 Questions a Day. If you See I am Maxxed Out, then Try Submitting your Question at or Just After 8pm EST (US). My New Day Starts then. Thanks.
Respectfully
John
---------- FOLLOW-UP ----------
QUESTION: Hi John,
I have followed your suggestion and opened up the crankcase breather. It is as clean as the day it left the factory and seems to be operating perfectly. I also pulled the carb off and the plastic insulator. It also was as good as new. The passage was clear and the little flapper appeared to be doing what it is supposed to be doing. The thing we can't forget as we trouble shoot this is that there was no gradual deterioration in performance, this condition appeared virtually overnight. Do you suppose it could be a valve timing problem? Could the timing belt have slipped a tooth? The unit is a 1986 (SN EA1-1012504)with possibly 250 hours on it. Should I be thinking about valve clearance? But this would be a gradual thing where this problem just came on like you throw a switch. My buddy next door has the same machine and he clearly has good vacuum where I have this 5 PSI pressure.
We are all going to be much smarter after we figure this one out.
I thank you in advance for your efforts.
Best regards,
Dennis Waters
AnswerHello Again Dennis:
We Moved the Timing Belt on 1 of the Honda Engines in the Shop and it Appears you May be Correct. If the Belt Jumps 1 Tooth, then you Start Getting Pressure to the Vacuum Line you Described. If the Belt Jumps 2 Teeth, then the Engine will Not Run. The Timing Belt May have Jumped a Tooth and Requires a New Belt. Usualy if the Timing Belt Jumps, the Engine will Not Start or Run, however, the Belt Usually Jumps More than 1 Tooth. If you Hit a Snag or this Does Not Correct the Problem, I am Here if You Require More Assistance. Hope this Helps. Let me Know What Happens, Please. May the All Mighty Bless You and Yours. Thanks.
Good Luck
Respectfully
John
PS: I am Allowed to Answer 10 Questions a Day. If you See I am Maxxed Out, then Try Submitting your Question at or Just After 8pm EST (US). My New Day Starts then. Thanks.
Respectfully
John
