First off, for clarification, you have the FR730V. Just a typo, but want to avoid confusion.
Hustler owner here who almost bought the EXACT same machine. You chose well! I didn't buy it because a gently used Hustler landed in my lap for $400, and I couldn't pass that up. I've serviced the FR691V and FR730V. In the manuals, it shows the temperature/viscosity arrow diagrams as SL 10W-30/10W-40. However, printed on the factory dipstick, it clearly states "10W-30" on both of them. If you call Hustler, they tell you any XW-30. If you call Kawasaki, they tell you SM/SN/SP 10W-30 is bad, and if it's not SL 10W-40 it will spontaneously combust (so it begs the question: why does Kawasaki's engine dipstick say 10W-30?). Then again, this is the same company that says "using multi-grade oils will increase oil consumption."
Directly from the Kawasaki Owner's Manual for FR651V/FR691V/FR730V engines:
View attachment 58552
I can assure you that the FR691V I have serviced since new has had nothing but passenger car SN full synthetic 5W-30 since the recommended 8-hour dump of the factory fill. It now has somewhere between 1,100-1,600 hard hours on it (no hour meter). It has never smoked, used any oil at all, or even once required the choke to start. It just fires up quickly (
As for the filter, Kawasaki's filter is the 49065-7007. These are expensive, tiny, and ignorant to use. These filters cross exactly to a WIX 57035, NAPA Gold 7035, or Fram PH8170. I use none of the above, and I'm one of those people who hates using alternative parts. I use the WIX 51348/NAPA Gold 1348/Fram XG3614. It has all the same specs, just increases the oil capacity slightly (a good thing), has more filter media, and is MUCH cheaper. You can also use a WIX 51516/NAPA Gold 1516/Fram XG3600 *IF* you have the clearance to get it in and out of the mower. This would also further increase the oil capacity. On the Hustlers, the 1516/3600 doesn't have enough space for my liking, so I use the 1348/3614. The bonus is it usually takes a perfect 2.5 quarts with this setup, so you can buy a 5 quart jug and be set for two oil changes. I've used the 1348 since the 8 hour dump also. Again, 1,100+ hours and still runs perfectly. Since you didn't list the Fram Ultras you have on hand, my advice is don't use them unless they are the XG3614 or XG3600 (there isn't an XG8170). Bypass valve settings, burst pressure variances, and flow rates are my reasoning for recommending only those two alternatives and not others that are "similar" or "compatible" yet very different internally.
Also, the factory air filter/cover setup tends to get a LOT of dirt and grass in it. Keep it clean. A little compressed air works wonders (gently! Don't blow contaminants through the filter. Blow out, not in). The Kawasaki air filters work best (especially the pre-filters!).
The spark plugs should be NGKs. 6578 and 7222 are identical other than the 7222 has a screw-on wire connector (inferior and pointless IMO). 6578 FTW.
And most importantly, check the oil level WITHOUT screwing on the dipstick!
