Changed the hydro fluid today. It was pretty nasty, I don't feel a difference after the change but I'm glad I have some nice clean oil in there. I still have some speed surge (lurch?) Unfortunately I know what the problem is (trunnion bracket) after only a few days of browsing on this forum.
I am not really wanting to split the tractor to get at that piece of metal. I sort of got a peek at it today, it's got some side to side slop when I touch the spring. It just feels loose overall, I can't really get my head in there far enough to see if there are notches. Anyhoo, still happy with the tractor... I like projects.
I am still having problems with it shutting down when hot. Per the advice of a few on here I think a new coil, new points, and a Kirk pointsaver (eliminate condenser) will be a good starting point. I can see this will be a happy little money pit already.

I got a new gasket and filter for the hydro from my local shop. They had these pretty little 'O's' inside the parts department!!

http://imgur.com/i6ysFI5
http://imgur.com/i6ysFI5

http://imgur.com/i0s7WXI
http://imgur.com/i0s7WXI

Parts for the job.

http://imgur.com/gD0hClA
http://imgur.com/gD0hClA

Filth, but hey - found the serial number (it's a '66 I think)

http://imgur.com/oNHOImG
http://imgur.com/oNHOImG

I've changed cleaner diapers.

http://imgur.com/S9MfaY2
http://imgur.com/S9MfaY2

Found some crud, not too bad I guess compared to some pics I've seen.

http://imgur.com/xwKGPy6
http://imgur.com/xwKGPy6

I'm amazed by the condition of these 48 year old parts.

http://imgur.com/CzCWKUh
http://imgur.com/CzCWKUh

Honestly the biggest PITA was cleaning old gasket gunk, otherwise a pretty easy job.

http://imgur.com/Z7dzhPn
http://imgur.com/Z7dzhPn

All clean!

http://imgur.com/RKyMk1K
http://imgur.com/RKyMk1K

I took a can of carb cleaner and got the gunk off the pump right quick. Pretty impressed actually! It was nasty, I should have taken a 'before' pic, it was worse than the rest of the tunnel you see here.

http://imgur.com/GTt7qc3
http://imgur.com/GTt7qc3

I think that job deserves a frosty beverage!! :beerchug: (went over my pic limit and had to post again.)

http://imgur.com/HCz3DOU
http://imgur.com/HCz3DOU

Splitting the tractor is about a 1-2 hour job if you've never done it before. At least it is on a WF. I can't imagine a NF would be much harder?

In regard to your dying condition, I would still recommend you check for spark while the motor is HOT and work backward from the plug wire to find what the problem is.

Otherwise, good work and thanks for the pictures! Working on my neighbors green mower is getting me down so it's nice to see yellow again :)

Yes thanks, haven't forgot about your advice. I will check that this weekend and also check all the fuel lines. If there is indeed poor or no spark at the plug side of the wire when hot then I have a failing coil correct?

Could be points, coil, condenser, wiring, etc. That's why you have to work the problem one step at a time. :) Even if you replace everything all at once you may not fix the problem or even get a new parts that is defective and have to start at the beginning anyhow. Good luck!