Ben, the parts and manuals section has the full workshop manual for the 194 and 214 Honda mowers. The 194 and 214 have the GXV120 engine. With Honda model numbers, the G means Honda, the X usually means pushrod, and the number is the capacity in cc. The V, if it has one, means vertical crankshaft. No V means horizontal crankshaft. The GX120 and GX160 engines are rather similar except for bore, stroke, and fuel tank size. (They both use the same owner's manual.) The horizontal and vertical crankshaft basic engines are quite similar except for specifics like the oil slinger arrangement and the oil sump. So, you can probably get the information you want from the HR194 workshop manual, which is fairly detailed. Incidentally it does not show or mention any valve stem oil seals. I don't personally know of a mower engine that has them.
If possible, when you do the engine repairs please take a few pictures and post them here. In particular, if you can measure the piston ring gap with the rings inserted into the bore 10 mm from the top (use feeler gauges), and show how the ring grooves in the piston look before you clean them, that will make this thread more useful to other members as an archive. It helps people to get a sense of perspective if they know how much ring gap it takes to give lousy compression and heavy oil consumption.
Don't forget to check the fit of the valve stems in the guides - details of sizes and clearances are given in the workshop manual. You can also get the dimensions, and a way to measure the stem clearance, in this thread:
https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=23913&page=1If you measure the valve stem clearance as described in the other thread, please post a picture of your setup.
