I am not trying to hijack the 1700 thread, but a lot of the 1700 stuff looks a lot like the 1500 stuff...I am currently working on a 1500, but did use it a while to see what I had.
Mine is in landscape-dress like your 1700 I see here in the pics. I have had small hp "other tractor brands" and have came to the conclusion these 1500-1700's are built a lot like a tank in some respects as opposed to some of the other Japanese tractors. I am not knocking Kubota or Yanmar either....just making an observation about what I can see vs. what I have owned.
The parts are pricey like mentioned above, but I have found several items off e-bay and other sites along the way. I re-wired mine too and eliminated a lot of unnecessary (for me) junk. Like....why do I need a horn or flashers! I also removed the safety switch at the clutch-pedal, but that is a matter of your feel for personal safety. In my view....any possible link in the chain that could cause trouble, I remove it if possible. My wiring at the alternator looked about like yours does, so I re-worked all that. The harness is not that long and once you peel-off the old tape, most of the existing wiring can be used. When I first reconnected my burned-off lead to the alternator (was not charging when I bought it)...I blew all the headlights as the voltage shot up to around 16v. I replaced the mechanical regulator with one off e-bay for around $30 and solved that problem.
My main issue at the moment is steering slack. My cross-shaft actually moves a good bit when the wheel is turned, so I am in for a replacement load deck or bushing....if there is a bushing in there. This will be my next venture to get into. I might wind up at the machine shop as opposed to giving somebody $600 for a new load deck.
These other guys have done a lot more stuff to these little 15 and 1700's than I have, but I will be happy to help you solve anything I can. You are walking in my tracks! First thing I'd do is consider that battery tray. On mine...the battery had rubbed the radiator and I sprung for a new radiator and re-worked the battery tray with one from a Chevy pick-up that will not move.