HRX217HYA No start

I can pull the valve cover, but what am I looking for?

I'll assume just normal operation, and opening and closing of valves.

Correct, and if either valve develops excessive clearance due to not closing. If so, you might be able to push it further open and free it up . . . I have heard of a few cases where engines that inadvertently had a valve fully open when shut down had it stick open after storage. If you have a compression tester, that would tell you as well.

tadawson said:

That pretty much leaves timing or a stuck valve . . . I don't recall . . . have you checked compression? Easier to pull the valve cover than the flywheel, and I can see a valve binding in storage, but not a timing shift . . .

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And the ignition timing.
And the valve lash
Mechanical things are the easiest to check.

I said timing, and lash doesn't automagically change when you put the mower away (running fine) for the season, so I tended to leave out the seriously unlikely possibilities at this time. (And frankly, since it was running when he put it up, I doubt this is an ignition timing issue either . . . . again, something that does not happen from sitting not running . . .). My favorite right now, since fuel appears to have been verified is a hung up valve . . . that can and does happen from sitting idle . . . albeit rarely . . .

Not meaning to get into a big blue, bu a single backfire can crack or split the the timing key.
An engine with out of spec valve lash can work fine all season but when left over winter and the oil drains out of the ring slots can become impossible to start next season
And yes a stuck exhaust valve is very common over winter but that would not cause a pull back and excessive compression unless it was causing coil bind on the valve spring.
A stuck inlet blows back through the carb.

It is one thing to have the mower in our respective workshops and another to have it at some one elses house and a person other than ones self working on it.
I have a proceedure of testing a non starter and I am sure you have one that works just as well as mine.
However we are working with some one with limited knowledge , understanding or experience so we have to cover all bases , from first principles.
In my case it is fuel availability which has been verified .
Next I go to spark timing which is very easy to verify for a small engine novice as it is visual .
After that we go to harder to verify things like a stuck ACR, stuck valve, out of time engine.
What has come into the workshop was an engine that jumped a tooth on the timing belt because the belt got dry and rusted onto the cam sprocket.

I gotta admit, my mind has been centered on the GX engines, which, being gear timed, you pretty much have to break the block, cam, or crank for them to jump valve timing if it has not been opened. And I still doubt that his engine could have backfired while in storage and lost ignition timing . . . I agree that happens, but the result is typically immediately visible, not months later, and timing shouldn't move simply due to trying to start it . . . unless the flywheel nut is both falling off *and* the key is broken, which was pretty much contradicted when he said it would not come off (the loose nut at least). As long as the flywheel sits on a taper, I doubt the key sees much of the load *if* the torque is correct, acting more as an installation alignment aid, but never say never . . .

But, as noted, I don't do much with the consumer grade Hondas, so they may well have quirks I don't see in a GX series . . .

So, we agree to check most to least likely, easiest to hardest . . .

I assume from all of your attempted work that this machine is out of warranty? I know the model has been around for a while but these carry a 5 year consumer warranty. Either way, these problems can be frustrating especially when these Honda engines are typically reliable. I had an issue with my HRX where I tipped it the wrong way (carb down) and oil got past and into the carb. It resulted in a carb replacement and some trouble connecting the rods for the auto choke before I was able to get it to run. I am sure that with your extensive work on the fuel system that the issue is more "mechanical" in which I know nothing about. It might require a complete tear-down to figure out what is going on. I am not sure of how much time and money it will take to repair the engine but a new engine can be had for under $200 or a used one can be pulled off of a Honda powered pressure washer or something similar in which the engine can be fitted up without modifications. Just a thought. . . . .

Sorry for the delay in getting back to everyone. Decided today after putting it all back together... and pulling the starter rope a few dozen times, that it indeed is headed to the Honda repair guy. I just don’t have any more mornings to waste on this mower. I feel like I could have found the problem, and I am sure in the end it is going to be something really stupid.

Thank you to everyone that tried to help troubleshoot with me. I will let everyone know the outcome.

Joe

Mower back from shop....they did a normal service of- Changing Plug, Changing air filter, cleaning carb and changing the oil. They also sharpened the blades.

I am told that the "belt was off, and wrapped up, and that is why it would not start" . I never did check the drive belt or see if anything was wrapped up??

All I know, is it starts first pull.....

Thank you again for all the trouble shooting help!

Joe