A couple weeks ago, a coworker said he picked up a Honda lawnmower with a free sign on it from the side of the road but he couldn't get it running right... Austen, do you want it? Hmmm, It's not often you find a free Honda anywhere so it must be pretty beaten down and neglected, but sure, I'll take a look I thought as I do like these mowers.
When I went out to see just what it was, I wasn't expecting to find a lightly used, stored in doors type, HRX 217 with original manual and paperwork included! Even the wheels looked like they hardly had any use. Holy cow! Yes, I'll take it.
I gave it a quick fire up and it had a really bad case of the surges, almost embarrassing to run for any length of time. Should be a simple fix.
Okay, the usual, I ripped the carb off expecting to find a bowl that had never been drained and to my surprise, the bowl was as clean as the rest of the mower. Okay, well, most likely it has some gunk hidden elsewhere so I gave it a cleaning as best I could and reassembled. Guess what, it ran no different, surged liked crazy just as before. This mower has the auto choke feature so I researched the operation and tested the thermowax actuator but found that it worked correctly. Alright, this mower is completely worth it and carbs for these are cheap so I purchased a brand new one and a tune up kit with intake gaskets, etc, etc. Installed the new carb and.... rum, rum, RUM!! That surging was no different that before. Grrrr.
Alright, so I've got two carbs now, time a for a little experimenting or..... tuning?
The single adjustment screw had a limiter cap on it so I pried it off and took my Dremel tool to file a groove on the outside end for a flathead screw driver to turn. I played around with the adjustment of that to no avail, top to bottom, the mower still ran exactly the same no matter the position. I felt this was a lean running condition, they send these out from the factory to meet X, Y, Z, emission standard, expected to run on fumes. Again I thought, I've got two carbs here, not much to lose, so let's experiment around with one a little more. With success in the past of drilling out carb jets ever so slightly to cure a lean surge or an idle hang, I tried this in the jet of one of the carbs and, nope, no success there either.
So this was really getting irritating. I researched the cause some more for this particular model since checking off all the usual boxes to eliminate a running symptom like this wasn't solving the problem.
Someone I had found online who had the exact same model pointed out that his governor spring however was under-sprung and no longer had tension anymore. He said that he trimmed it and that cured the surging issue. One thing I did
notice and probably should've considered more was that the surge would go away when the engine had a load and I engaged the blades. I noticed the spring on mine was loose as well, so in normal fashion of not having much to lose at this point, I clipped the curl off one end, made a new one and reattached. Now the spring has tension and wasn't just laying flat. Fired up on first pull (one nice thing about the auto choke is that this thing does
start on first try every time), and VOILA, just like that, the surging was completely gone! It sounds like a new machine!! Woohooo!!!
Gave the mower a polish and wax, lubed up the cables, pulled the wheels off, and didn't even need to sharpen the blades.