In Reply to: 8n still sputtering... posted by Jim on May 19, 2018 at 20:04:58:
What do the points look like before you clean them? Look like a hot spot is forming, growing a fur coat or....?
How bad were the points you took out initially and how did the new set look when you replaced them? Points are pretty basic. THey either have continuity closed and none open or they don't.Easily tested.
I'm afraid to bring up the fuel system. Have you considered it may be fuel related. Engine stops for no apparent reason. You get off, find a card. Open the distributor and clean the points. In the interim enough fuel drains in to the carb get the machine running. Pretty basic question but does choking the engine when it starts to lose power help?
A quick test of the power to the coil can be done by hooking a test lamp to the hot side of the coil and the battery ground. Ignition on light on, ya got power. If it goes out while the engine is running and the tractor dies there in lies the problem, but since it sputters and dies it may not be. Worth a test as it's easy and easy is good.
If you have the blue plastic crimp on ends or worse Scotchlocs pay particular attention to them. Pull hard. One or another may only been hanging by a couple of strands especially if the wire is bent 90* from the connection. It may sound unnecessary but you have to start at the beginning with power supply
The ignition switch may be bypassing current into the primary circuit. Not a full 12v but enough to overheat the points and/or the coil, when the engine is stopped with the points in the closed position.
Does the battery discharge slowly? Not go totally dead but a little slow turning after a week of sitting? AN easy check for current draw is to hook a test light between the battery ground and ground. E.G. disconnect the ground strap and hook the light to the disconnected cable and the grounded (+ or-whichever side is grounded on your machine,) post on the battery. The light is now in series from the battery to ground. If you have current the light comes on even dimly there is a draw. Then disconnect the lead to the distributor. If the light goes out you have found a problem. Since you have a GM alternator disconnect it as I believe the exciter circuit is hot all the time.
Or......Bypass the whole primary circuit and go directly to the battery (or a remote) for power. If the machine runs OK you know the problem is in the the primary circuit. Switch, the boars' net of wiring around the amp meter ign switch, ballast resistor, etc.
Is the coil wired correctly and of the correct polarity?? It's 12v Neg ground I assume, and wiring a negative ground coil is pretty intuitive, but double Check it.
It may be difficult but if you can get your hands on a known to be good distributor and coil, install them. If one or the other solves the problem go through the distributor or replace the coil.. You may have to completely disassemble it to look for problems as suggested by others here.
BTW if you do disassemble the distributor free the advance weights if they are seized. You will be amazed at how much better your machine will run and how smoothly it picks up from idle to full throttle, no load and pulling.
If any or none of the above help you may have to disassemble the distributor and check for loose connections, a chafed wire, a small screw or washer dancing around inside or????. That copper strip giz which can cause problems.