On Wed, 29 Apr 2020 09:26:59 -0700 (PDT), wrote:

On Wednesday, April 29, 2020 at 12:00:51 PM UTC-4, Clare wrote:
On Wed, 29 Apr 2020 09:21:18 -0400, Leon Fisk
wrote:

On Tue, 28 Apr 2020 05:20:06 -0700 (PDT)
wrote:

Huge snip
Hi Clare, others. I tried the smell test the other day.
It's got more of an oily smell than the gas I smell when I leave the choke
on. TBH the black plugs are not that much of a problem. I clean 'em
in the spring and maybe another time during the summer. I did check the
float level and that looked spot on.
I do love this old tractor. I had the head rebuilt a few years ago.
With any luck she'll out live me. :^)

Found a nice service manual here (~55mb):

http://www.ntractorclub.com/manuals/...e%20Manual.pdf

===
Per that manual you should have a "Delco-Remy Model
No. 1111722 with crankshaft rotation advance of 26 and 24 degrees
respectively, both models are fully automatic..

The centrifugal advance mechanism is in-
corporated in the distributor to automatically
vary the timing of the spark with respect to
the position of the piston in the cylinder. At
high speeds, the spark must occur at the plug
earlier in the compression stroke In order for
the fuel mixture to deliver full power.
The advance mechanism consists of an ad-
vance cam, breaker cam, a pair of ' advance
weights, springs and a weight base that is In-
tegral with the distributor shaft.

At low speeds, the advance weights are held in to-
ward the center by the spring tension. As
the speed of the distributor shaft increases,
the centrifugal force overcomes the spring
tension and the weights move outward and the
toggles on the weights engage the advance
cam. This rotates the advance cam and break-
er cam which in turn allows the breaker cam
to open and close the contact points earlier,
thus advancing the spark...
===

Maybe help you out some ;-)
I really suspect it is oil.
Interesting to know what oil is being run and when it was last
changed. Like I noted before I'd be putting some MMO in the oil and
running it for a few hours, then drain the oil and refill with 15w40
all fleet (like rotella T) or 20W50 Castrol GTX or similar and see
what happens. Quite possible the valve guide seals are poor but he
DID say he had the head rebuilt recently so more likely the rings. The
rings tend to sludge up and stick - and the MMO (Marvel Mystery Oil)
or Shaler Rislone can loosen the rings. I used to use Rislone years
back but MMO is a lot less harsh and just as effective.

I changed the oil and filter last year... I filled it with cheap
10W-30. OK when I change the oil again... a few years, I'll try
some of your magic oil. (Well maybe... maybe it's better
to leave sleeping dogs lie?)

Thanks for all the nice 'tractor talk'. My neighbor down the road
had a Ferggie too, but he passed away few years ago and everyone else
around here has newer fancier tractors.

George H.
Personally I wouldn't use 10W30 in that tractor, and with the little
use you give it I'd change it every spring. I've never had MMO cause a
problem in an engine - and I've used a lot of it over the last 50
years. I'd run Rotella T3 or T4 15W40 or Valvoline 15W40 all fleet
premium or E900. That engine wants the ZDDP levels up around 1000 or
more. You won't get that in any current 10W30 or any current
"automotive" oil less than 20W50. The crancase ventilation is sub-par
so moisture build-up and sludging can be an issue if you don't change
it often and only use it sporadically for short jobs.