I have seen a lot of posts lately about magnetos and pony motors. Heres what I've learned over the years, its always best to leave the Magneto on the Pony motor whenever possible. The majority of your problems will always be dirt and corrosion from not having a properly sealed cap. Order a new gasket between the Magento and the cap and always keep one on hand. Remove the end cap from the Magneto, carefuly pull of the rotor. They have the tendancy to get stuck and if you pry on them they will break. Take sandpaper, never use emery cloth. Sand the rotor or you can use fine steel wool. Use a points file for the points. Some people use sandpaper, one of the best things I found, if you wife doesn't catch you, use her memory board (finger nail board) and file the points. I have noticed a tendancy for the tension spring on the points to become weak. Please check it while you are there. Point gap should be around 15. This usualy solves the majority of the starting problems. Also, sand the cap and the coil, copper spring that the cap touches. Sandpaper works the best for this. I bought a digital fence tester, for an electric fence used for farm cattle, and it works very well. While you have the cap off you can take the electric fence tester, hold it to ground and clip it to the coil. You can rotate the engine with the Magneto still on, till you come to the inpulse starter on the Magneto, and when it makes a snap you should have a reading. Anything below three, you have a weak coil or a weak ground. This will also tell you the fifth part of the Magneto is working. If your points are good and the rotor is good and you have cleaned them you can put the cap back on and make sure the condenser is working using the electric fence tester. If you have less or no spark or no reading on the fence tester, it is your condenser. If you want to clean the Magneto up while the cap is off, do not use compressed air, use a vaccum cleaner. A small hose quarter inch, works good to suck out any debrey or anything that is inside. But a good tight gasket between the cap and the Magneto will solve many of your problems.
Spark Plugs. I have had nothing but trouble with Champion spark plugs so I quit using them. I have found that if you use any other brand, perferable a German brand, I have had very good luck using them. I think it has to do with the ethnol in the gasoline. I have found that if you'll take 10ccs of transmission oil and but in your five gallons of gasoline I have less trouble with my gasoline engines that are old. I hope this helps, if your going to park your tractor for a long period of time, turn the switch off at the magento, leave the carborator full of gas, drain the small fuel tank, fill with diseal. Restart the pony motor with the gasoline that is still in the carborator. Once the gasoline is used up and the diseal fuel is in the pony motor and carborator, it will quit running. I have found this works very good over the winter. Drain out the diseal fuel, add fresh gas, and it runs fine.
Diseal fuel systems
Do not waste your money on fuel treatments on these older machines. Pour in five gallons of on road fuel that you buy at the station and it will clean out more than any fuel injector treatment that they make. They've got such cleaning agents in this new diseal fuel that it will clean an injector while you use it. Do not get carried away with on road fuel in these older machines. It's best to run off road fuel or a higher sulfur content than what on road fuel contains. Hope this helps, if you have any questions please reply. As always, this is what helps me, if you do not agree with what I say, that's fine, this is what I do and what I have good luck with my tractors. Old Man Dave.
Well done Dave
Great info there from a fella who has obviously been around old Cats for a long time, thanks for taking the time to share your experience, I agree on everything you say, and on the spark plugs I now use the Autolites on my old Cats, they seem to work well.
I spent a few hours talking to a 80 year old retired Electrical Engineer one day while trying to get a Eisemann G4 magneto working, he spent his lifetime building generator and lighting units for Australia after serving a 9 year Apprenticeship, he told me 90% of any magneto problems are the result of corrosion issues, in particular the points, so your advice about replacing the gaskets is another good tip.
All the best
I like the part about putting Diesel in the Pony tank while its running. It will do a "Top End" lubrication on the valves and piston besides sucking into all the jets and passageways to keep the Carb corrosion free! A plus would be it will probably keep the float from drying out and cracking, preventing float issues the following year.