May 21, 2013
Ok, this doesn't apply exactly to the mower you are looking at, but here is the answer I found regarding the HRX217HZA I just purchased last week. The private lawn specialty dealer where I purchased the mower initially sold me a model that I discovered had a "K3" designation. The "K" number apparently refers to small, yet sometimes significant changes Honda incorporates in any particular model. The K3 model of this mower has electric start and the Honda "Cyclon" battery, but the mower engine DOES NOT recharge the battery. Never. A separate charger is supplied with the mower, and the battery lid easily unsnaps to recharge the battery as needed. 24 hours is recommended to completely recharge this battery. The Cyclon battery is supposed to be good for up to 300 starts between charges.
Now, the K4 series of this same mower, was apparently released in January of 2013, and it has a smaller, more conventional sized 12v lead-acid mower battery, and the mower engine has a charging circuit built in, which eliminates any need for external charging... so an external charger is not supplied. Access to the battery requires the removal of 3 screws... no big deal. Honda claims that if the battery should require charging, say for example after a storage season, that a simple hand start and running it for about an hour will bring the battery back up to full charge. The external charger is available as an option for around $20 from Honda.
That's the only difference I could find between the K3 and K4 models of this mower, and Robert@Honda confirmed this on this forum. This seems to be a significant design change to me, so I think Honda should have made this difference more evident to potential customers and their dealers. My dealer showed me his parts manuals, which clearly showed a misprint regarding the charging feature of the K4 mower. So he was confused about this design change too.
Since I don't believe the HRX217VKA has electric start, I don't know what changes (if any) might exist between the K3 and K4 models.
For my purposes, the K3 or K4 model of the HZA mower both have advantages, but since I didn't know if there might be some other additional upgrades other than the battery charge change, I opted to have my dealer exchange the K3 for a K4. I have read that both models (K3, K4) are sold through Home Depot, so it doesn't seem to be related to what type of store is selling the mower. Who knows, a K5 model may be available by now?
Hope this is somewhat helpful. I'm sure you'll enjoy any model of this mower, since they all seem to share a solid design. Good luck!
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