• Home
• Magneto Rx:
• Eisemann
• CT-4 Caterpillar Magneto Service & Parts Manual

CT-4 Caterpillar Magneto Service & Parts Manual

The CT4-4 is an Eisemann product used exclusively by Caterpillar as far as we know on their gas powered crawlers and power units. It replaced the earlier wound armature design. It is a very robust design with fewer moving and wearing parts and is very hot and reliable even when all is not well. They are probably one of the most indestructible bullet proof magnetos ever made. Many gas powered crawlers are on the job today with their original ignition equipment. The CT-4 was later replaced by the CM-4. The main difference was a more modern rotating magnetic armature and not a horseshoe magnet. Pyherwise very similar. Both excellent magnetos. here is some factory service and parts info to keep crawling.

 Now you know what that brass plug on the side is for.

 The condenser can sometimes fail. Always test for electrical leakage with an automotive condenser tester. These can be retrofitted wuth a 0.22Microfarad 400 volt capacitor designed for spike currents. We like the Sprague "Orange Drop" capacitors. More on this later. 

 If you need to pull the rotor and the large castle nut taht retains the timing gear does not come peacefully do not force it. Add some heat with the acetylene torch. The threaded end of the armature shaft can(will) break off if the nut is seized and excessive torque is applied. Don't ask is how we know that. Get it red, let it cool, then it should let go. Note the double keys and witness mark on the steel gear and index with the marks on the brass distributor gear.