Honda has been not very organized when come parts look ups. Sometimes the serial entry won't work so you have manual search thru a list of mowers and match up the serial number range. Especially with engines.
As with this model the serial number when entered comes up as the K4 revision. This just you have know to add the K to model number revision level. And sometime there is an extra "A" added for the American built units. Again something you just have to know about. And the engine is a GCV-190A but you wouldn't just find the engine with type code MX1.
But I do use
https://peparts.honda.com/powerequipment#/browse for complete mowers look-up. And you can't just look-up the engine either as they consider part of the complete mower and Honda will not provide a separate engine IPL when it is on their equipment. I know it seems stupid but this is the way Honda does this. It does become a problem if someone has transplanted an engine from another model or revision level. This where I usually inscribe the replacement info the mower for the future tech to find parts. It also goes in my customer files locally.
Engine sold for use on other equipment are looked under engines. But have to search the engine code and forget using the serial number. Basically you look up the engine code then go down the page and use the type code.
Using a site like
https://www.honda-engines-eu.com/en/spare-parts or
https://www.boats.net/catalog/honda/small-engines where you search a list of various engines matching up the type code and serial numbers.
BTW most of my Honda parts comes from Boats.net which is a division of Partzilla. Not to be confused with Partstree.
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