Need help with Honda carb. Not running well.

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  #1  
Old 01-10-08, 07:49 PM
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Question Need help with Honda carb. Not running well.

Each Spring and now Winter, I am having to have my mower's (Husqvarna 55R21HV/Honda engine) carb serviced due to an apparent gummed up carb. The shop claims ethanol in the gas now days is presenting this problem moreso than in the past. Apparently ethanol draws in moisture and dilutes fuel. Anyhow, I took the advice of a few experts and cleaned carb (disassembled and sprayed carb cleaner, not bathed. I plan to do this weekend), replaced with new air filter, oil and plug. Once I got it to start again, it's now reving up and nearly stalling before it revs up again. I can see the linkage and springs moving back and forth trying to keep it running. The automatic choke rotates to non choke or open position if termed correctly. With the air filter off, I can see it is open. But the linkage above the carb is constantly moving cuasing the engine to rev and nearly stall. What may cause this and how do I solve?
Thanks,
SW
 
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Old 01-10-08, 08:38 PM
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i would disassemble the carb and give it a bath in bath type cleaner then spray it with carb cleaner then rebuild it. i was told you can't get kits for honda carbs you have to order each part by itself.
 
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Old 01-11-08, 12:43 AM
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It is still the carb in need of cleaning causing the surge. I also reccomend using a bath type cleaner to clean the carb. Are you using this engine once every few months? The fuel shouldn't be gumming up that fast. I don't know about ethanol fuel...don't have it here. Are you buying fuel advertised as having ethanol in it?
 
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Old 01-11-08, 04:38 PM
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I am bathing the disassembled carb tonight and will spray with carb cleaner just in case. I did notice today while filling up car at Exxon that they do advertise 10% Ethanol. I have heard from a few people that this can indeed cause problems. I plan to search tomorrow AM for fuel without and then try this again. Do you suggest spraying spark plug hole with cleaner for easier starting? I do run my mower at least once/week give or take during months of March-November. BTW, how tight should I turn the screw that is seated into carb, not the bowl screws? Does it regulate anything?
Thanks for all the help.
SW
 
  #5  
Old 01-11-08, 06:16 PM
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I had to deal with a troublesome Honda carb last month (snowblower), it was chasing just like yours. Turned out the bowl had tiny punctures due to undetected long-term water contamination. At first I suspected that snow had been sucked into the carb through the air cleaner (snowblowers don't use air filters so this is theoretically possible) last winter leaving condensed water sitting in the carb all summer long so I bought a new carb which solved the problem once and for all.

However the other day I had to go to the Honda dealership and brought the old carb for a post-mortem. The guy had one look at it and said one of the adjustment screw was missing. There are only two of those and the smallest one (the pilot) was gone which not only caused the carb to malfunction but also let water seep in. You should check if both adjustment screws are still there on yours, could be as simple as that.

Other common causes for engine chasing are leaky bowl and/or fuel strainer and damaged head gasket(s), among others.
 
  #6  
Old 01-12-08, 06:38 AM
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Hondas with surging throttles are very common. I haven't met a honda that didn't surge. In my experience with these engines is when you disassemble the carburetor, you have to use a small screwdriver and pop the brass nozzle out of the center stem of the carb. there are little tiny pin-holes in this that clog up VERY easily. Some pop out easy and some need a little finesse to get them out. This nozzle is held in place by the main jet in the tube the bowl nut screws into. You can also see it poking into the venturi of the carb when looking straight through it. Also, when soaking honda carbs there are a few plastic parts you must remove if you haven't already. The black phillips head screw that adjusts the idle needs to come out and the black plastic thing it holds down also has to come out as this has rubber o-rings on it. I hope this helps in some way.
 
  #7  
Old 01-14-08, 09:29 AM
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Originally Posted by Legal v8 View Post
Hondas with surging throttles are very common. I haven't met a honda that didn't surge.
I have. My Hondas have never surged until the bowl was removed for a first time so from now on it'll never come off unless absolutely necessary. The rubber gasket apparently can't survive exposure and fitting a new one properly has to be done following some mysterious occult ritual otherwise it'll leak which causes surging. That gasket looks weird, never seen one like it on any other engine.
 
  #8  
Old 01-14-08, 10:42 AM
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this is why i don't rebuild honda carbs. i just replace them. too much hassle + they don't sell carb kits you have to get each part by it self and that adds up in $$$$$$$$$$$
 
  #9  
Old 01-14-08, 11:13 AM
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Originally Posted by flirty1 View Post
this is why i don't rebuild honda carbs. i just replace them. too much hassle + they don't sell carb kits you have to get each part by it self and that adds up in $$$$$$$$$$$
Yup, and proper documentation is hard to come by... until you stumble upon the wealth of info Honda provide its customers with in Europe. Even for a dealer it's a hassle to get a shop manual for Honda engines here but on the European site it's available for free in PDF format. Check these out:

Honda carb check sheet:

http://www.honda-engines-eu.com/en/images/59138.pdf

Honda engines shop manuals (under "Service/Service Information"):

http://www.honda-engines-eu.com/en/welcome.html

 
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