It seems an appropriate time to bring this magneto thread back up the list as winter hopefully soon works it's way out and keeping our fingers crossed for some good spring and summer weather in 2013.
I am sure we will soon be eager to have some of our tractors filled with water and running again in the next few weeks so thought I would discuss my recent experience with a Bosch U4 magneto fitted to my restored 1937 Green Pacemaker, the magneto was fully rebuilt in about 1987 and since then I could gaurantee that tractor would start on the third pull up of the crank, two with choke out, choke in and the third she would be away, no matter how long it stood without being run it always started the same way, so easy and effortless and never touched the magneto until now.
At Christmas this year decided to give this tractor a run, put gas in the tank, filled it with water and expected on the third pull up it would be away, well after several cranks it fired once, which encouraged me to crank more, knowing there was something wrong I kept cranking and eventually it started up and run well, but it should of started much better, so left it running for about an hour.
The next morning I decided to start it again, expecting it to go after three pulls, it would not even fire or cough, so took the points off which were coated in a green film, so thought here is the problem, a good clean with the points file and back together thinking it would start, still not a cough, so out comes the plugs to check if there was a spark, not a glimpse of a flash, so pulled off the distributor cap and about to start removing the magneto to try Joe's revival method or send away for rebuild something said to me wipe the fibre distributor wheel with a clean cloth, I took my handkerchief out of my pocket rubbed around the wheel including the brass insert, looking at my handkerchief it was covered in black soot, carbon from the brushes I expect. I put the cap back on pulled the crank up twice and she ran like a swiss watch and back to it's usual self of starting on the third pull.
I just wondered if anyone else has experienced this with their magneto's?