1952 8n no spark (kind of long)

I am having trouble with a 52 8n side mount original 6 volt system. I have been using the tractor with a finish mower to mow about 1.5 acres with no problem. The last time I cut it seemed like it cut out or sputter, but kept running. It was a little hotter ambient temp, in the 90’s when it sputtered slightly.
But now I am using a 5 foot rotary cutter on 5 acres of heavy weeds, so much so that I only take a half of a cut where it is heavy. Also the weather is in the lower 90 degrees while I am doing this. I can go about 6 rounds around the field and it will start cutting out, I thought it was fuel related so I checked the flow and the screens and they were all ok. I went out to cut again and same thing 6 rounds and sputtering under load and cutting out. Still seemed like fuel so I pulled my carb off a 1950 that has been running good and put it on it. I had a set of new plugs so I swapped them out, the old ones were ok, brown at insulator maybe running a little rich but not wet.
went out again and the same thing 6 rounds and sputtering and cutting out. This time totally died and would not restart, so I waited (of course I was in the field farthest point from the house) and let it cool down some and got it restarted (it ran but still sputtered under load) and headed for the house, there is a long hill back to the house and it started sputtering again and I almost did not make it.
So now I am thinking electrical. I had a coil off of the 1950 I am restoring, the only reason I changed it out was I did not want a scratched up coil on my freshly painted tractor. So I know it is good, used it on the 1950 tractor for about 8 hours before I took it off to paint that tractor. Put “new” coil on and the same thing, sputtering and cutting out after 6 or so rounds. Now I am thinking condenser, I had one laying around so I swapped it out and now no spark. Put the old one back in and still no spark.
I did a little checking and I have 6 volts at the coil (from switch) and out , to points, at the insulator on the side of distributor, and at the points. Still no spark. I even hotwired it still no spark.
I have cranked it so much I thought battery might be low (and my patients running thin) so I thought I would quit and put the charger on the battery overnight and look at it again in the morning.
The tractor does not seem to be overheating, no steam out of radiator, I have a screen over grill and I keep it cleaned off. I have no temp gauge.
Other work I have done on it recently:
New wiring harness. I did that while I had the tractor split to fix a loose oil pickup tube.But it has been running ok all spring, mowed with finish mower 4 times.
I have adjusted the linkage to the governor, I know the governor is in need of repair but it is tolerable, I am waiting on parts for governor (I don’t think this is related to the sputtering) The governor on the tractor is for one without a proof meter but I have a correct spare with proof meter connection.(waiting for parts)

Any suggestions would be greatly appreciated.

"I have 6 volts at the coil (from switch) and out , to points"

Obviously you know what you are checking here.
Does that voltage drop to zero with the points closed as it should?
Could it be as simple a needing a new set of points?

Royse, I checked the points and polished them with a dollar bill, I thought they looked good not pitted. I also had checked the voltage while cranking and it did not
drop to zero, I thought that was odd, it went from 6 to about 31/2. It would zero out with points closed. It was an old analog meter that I liked to use on these old
tractors but then I knocked it off the front wheel and broke it.
I think I will get a new set of points and condenser and start on it again this morning.

(quoted from post at 07:56:21 06/13/16) Royse, I checked the points and polished them with a dollar bill, I thought they looked good not pitted. I also had checked the voltage while cranking and it did not
drop to zero, I thought that was odd, it went from 6 to about 31/2. It would zero out with points closed. It was an old analog meter that I liked to use on these old
tractors but then I knocked it off the front wheel and broke it.
I think I will get a new set of points and condenser and start on it again this morning.

Click to expand...

ou will get some 'average' voltage reading (more than zero & less than 6) while cranking (or while running), but it should go to zero when stopped with points closed. An incorrect gap will result in 'sputtering', too.

Royse, You nailed it, I put new standard ignition points on it and it started right up. I am heading out to see if it still sputters after 6 rounds. JMOR thanks also, I
wasn't aware that the wrong gap would do that. I had checked the gap and polished the points but maybe it was just cheap points? This is a new to me tractor so I
don't know the history but it had been running good, heading out to test it now.

Glad to hear you got it running.
Hopefully that fixes the sputtering too.

Yes I got it running and finished the field. I had put the old carb back on it as I was pretty sure it was not a fuel problem. The field is long hillside, (it is Kentucky LOL)
with 3 different valleys in it and I experienced a little sputtering sometimes going into and out of the valleys. It never came close to dyeing out. Then on the last round I
went into a valley and it died, would not restart, but kicked a little so I knew it had spark. DUH opened the reserve tank and was able to get it started but it would only
run if I pulled the choke partially out, so now I think I think I have a fuel problem. I will check the 3 screens again. I was going to rebuild the carb when I got some time,
but it sounds like there is no time like the present. I don't see any rust in the tank, but it is an aftermarket carb (plated not painted) so I think I will rebuild one of the MS
carbs I have and put it on it.
Thanks again for the help, I always learn something from all the people who are willing to take the time to share their knowledge. Maybe someday I will be confident
enough in what I have learned that I will be able to answer some questions too.

"DUH opened the reserve tank and was able to get it started but it would only
run if I pulled the choke partially out, so now I think I think I have a fuel problem."

i had this happen to me after installing a new sediment bowl. the cure was putting more gas in the tank. the (brand new) reserve was already plugged, and only letting a small amount of gas thru. once i switched to the main, all was well.

check flow out of the carb drain on reserve, and see if it's just a trickle instead of a good strong flow.

My 8 n's did the same when using a 5 ft, bush hog and I discovered from a friend that it could be vapor lock as the fuel line is only sev. inches above the cylinder head and this only happens with heavy loading on hot days -- I wrapped the fuel line from shutoff to down bend loosely with crinkled alum. foil and now both my 8 n's run as long as I need them . Acts a as good diffuser for the heat