All GXV140 engines were made in the US. At a guess, they initially had the Made in USA insert and it was dropped along the way - I have no information on that. All GXV140s had the serial number prefix GJAB, and no other Honda engine had it (that prefix is the most authoritative way I know to identify Honda engine models, by the way). All serial numbers fell into the range 6000001 to 7999999. The minor differences along the way are denoted by the "Engine Type", which for both of yours is MAC*. There are no references in the records I have to the trailing star, but every GXV140 in Australia that I've seen or heard of has the star - it may be an export identifier, but that is simply a guess. The Engine Types for GXV140 range from A1 to N2Y. All of the GXV140s in Australia that I've heard of so far, have Engine Types beginning with MA and ending with the star, but the intermediate letter so far runs from C to J. In case it helps at some point, the Paper Parts Catalogue Part Number for MAC engines is 10ZG901AP - this might be relevant at some time for buying parts, I don't know.

With well-used vertical Hondas, always inspect the brown fibre and resin PCV valve disk for wear. Every time it opens (every downward stroke of the piston) it hits the depressed part of the PCV compartment cover - circled in red:

[Linked Image]


This very slowly wears the disk away. You can see the wear depression in the one you photographed - the wear looks rather slight as far as I can see in your picture. Here is the worst one I have had so far:

[Linked Image]

I haven't been desperate enough yet to re-use that one: it is worn most of the way through.

I haven't yet seen an early enough engine to have that boss on the cylinder head that is on your older engine but not your newer one. Here is a closer view of that part of my spare MAH* cylinder head:

[Linked Image]

That is quite a substantial design change - my guess is that it was done for a good reason.

You will notice that while both of your engines have bosses for the mountings for both N and A type ignition modules (see other thread for explanation) in the older engine there does not seem to be a cored hole in the N type boss (GXV140s were only fitted with A type ignition modules). In your later engine the third boss has a cored hole, but it was not tapped. My MAH* cylinder head also has the cored-but-not-tapped third boss.

Now that I've gotten so far into the esoteric detail, I'm morally obliged to move this thread to Tech Talk.