DISTRIBUTOR
I feel that the front mount distributor on the 9N, 2N and early 8N tractors has gotten some bad publicity that is not entirely deserved. Many people have commented on how much easier the side distributor is to work on. I did not find the front distributor to be a service problem. Remove two bolts, and it comes right off. The front distributor is driven directly off the front of the camshaft by an offset tang. Once you have the distributor in your hand, it can be taken to the workbench to replace points and check the timing.
I believe most of the bad publicity is caused by folks who are afraid to remove the distributor and attempt to service it in-place. Yikes! That is nearly impossible!
Unless someone has fiddled with the timing adjustment, it is probably ok right where it is. Once set it should not change, but then again, we seem to be having issues with low quality replacement parts. Depending on where you live, and your buying habits, some people have run into parts that simply do not fit right. If your new points are not made EXACTLY the same as the ones you are replacing, your timing could change slightly. There are stories where people have actually had to enlarge holes or drill new ones to get a new set of points to fit! My solution to that is to buy the highest quality replacement parts I can find. Then I return or throw away parts that do not fit right because I figure the time inferior parts will cost me just ain't worth trying to use them.
While you have the distributor on the bench it is easy to check and reset the timing adjustment if necessary.
Typical Step-By-Step Front Mount Generator Service
Remove Coil wire, Coil, and distributor cap.
Take note of the direction the rotor button is pointing. This is the direction it needs to point when the distributor goes back on. It will not go on any other way. Even if you forget you can hold the distributor to the front of the engine and turn the rotor until it drops into place. I think it is a little easier to know where the rotor should be.
Remove 2 bolts and take the distributor off. Take a look at the back side. You will see the offset tang that engages on the camshaft. One side of the shaft is noticeably wider than the other. This tang will only fit
on the camshaft one way.
Take the distributor where you can work on it. Install a new set of points and condenser.
Set the point gap to .015, then place a straight edge on the wide side of the tang
on shaft as shown in the attached photo. Rotate the distributor shaft in the normal
direction until the straight edge is 1/4" away from the outside edge of the
distributor mounting hole. The distributor points should just be starting to open.
If not, loosen the timing plate lock screw and turn to advance or retard the timing.
Keep adjusting until you get the proper 1/4" setting with the points just starting
to open.
This photo shows how to measure the 1/4" timing adjustment.
It is best to be turning the distributor shaft in the correct direction to the 1/4"
measurement. This will remove any slop in the advance parts. The 1/4" setting
will get your sparks firing at top dead center. That is correct for these engines.
When mounting the distributor back onto engine, the slot in the end of the camshaft
(front of motor) is offset. The tang on the distributor will only mate easily to
the slot on the camshaft one way. If you have it lined up correctly, the distributor
will fit flush to the motor without forcing it. If the tang is off,
the distributor will not fit flush to the front of the engine and if you try and
force it by tightening down the mounting bolts, the casting on the distributor will
break. It is not real hard to get things lined up right, but it is easier
if you remember about which way it was pointed when you took it off.
My 48 was very sensitive to timing and it had to be very close to dead-on Top Dead
Center for it to start easily and run right. When doing final tweaking to get it just right for your tractor you can make slight adjustments to timing without removing the distributor. Loosten the timing lock screw, shift the timing about half a mark, tighten the bolt and test it. Remember which way you turned it because you may want to go back and try half a mark in the opposite direction.
This simple trial and error approach, making small adjustments one at a time and then testing the results, has always seemed to be the best way to find that perfect final adjustments. No two engines are exactly the same and factory settings can always be tweaked slightly for better performance. The key is to keep track of each change so you can undo the change if there was no improvement or things got worse.