Honda hrb423 mower wont start have checked spark plug works any other suggestions pliz

Richard, take the covers off to get to the coil. un plug it and see if you have spark now. if you do you have a bad wire going to the coil causing it to ground out or the coil is bad itself. be sure you have a good plug in.

Put in fresh gas. Make certain gas is getting into the cylinder. Change the spark plug and that it is firing. Start your engine.

check for spark at plug if spark at plug then squirt some starting starting fluid in carb see if will start it should run long enough to burn out starting fluid if does check for water in gas if is drain tank and carb bowl put in fresh gas not and repeat not old gas you were using strat lawn mower if still dosnt start rebuild carb and add and additive called seafoam to the gas this is good stuff follow instrution on bottle

where do you spray the starter fluid in the carb or the spark plug hole?

If you say that everything is in working order and the engine should run............ I would check to see if you have water in your gas tank especially when a vehicle has been sitting for some time. Double check and make sure you have the proper fuel pressure as well. Hope this helps.

are you sure the fuel you added was good?gas is only good for 30 days in small engines

Check your key way. Might be cut or broke in half. Its the timing of the engine.

I have the GVC160 motor....same problems....just found this info (see link),...and it turned out that Honda used a NGK spark plug that was defective,....I couldn't believe that is all it was...after changing the carb (new),...adjusting valves....etc.. I just went down and bought a new spark plug.....and it runs great!!
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BEFORE go thru all of the advice and look at most other Honda web info.....go and buy a brand new spark plug and start with that! It appears Honda used a NGK spark plug in the past that fails after some time....giving the syptoms of problems with the carb, sticky valve, etc. Do not try to clean and use the old spark plug!! Check this out....it was the answer I was looking for after hours of work, reading, and talking to Honda dealers - http://forum.doityourself.com/outdoor-power-equipment-small-engines/261743-honda-lawnmower-starting-then-cutting-out.html

the pionts could be bad try changing them

You might have to change the spark plugs or at least have them cleaned.