6/24 UPDATE Our Supplier of these quality Onan B replacment coils we have be using for years is sold out and we have not ETA on when they will be back. That said we do have other coils here, the quality is the same but they are not speced the exactly same and have some small differences. But they will work, just maybe not as well. But if  a OEM one for roughly $100 MORE is not in the budget, then these are a viable option. We have the OEM coils listed and in stock if they are in the budget. 
 
C29752/C20349 Onan Coil "B" "BF" "CCK" Series. Onan Part Numbers (166-0772) (166-0535) (166-0804)
 
This is the correct coil for ALL points ignition Onan Powered 200, 400, and 600 series tractors/loaders that have a "B" "BF" "CCK" engine. Correct resistance for this coil is approximately 4.25 Ohms on the primary side and 37,500 Ohms on the secondary side. This coil has the same size positive and negative terminals. This is a quality aftermarket replacement coil.
 
There are options to Add New Spark plug wires and Spark Plugs To Your Order.
 
NOT for "P" series Performer electronic ignition engines, coil for "P" Series linked HERE.
 
NOTE: Some early model Onans may require a separate bracket/hole modification to mount this style coil. If your tractor still has the complete LONG cylinder looking coil that is completely circular from top to bottom long and skinny, then you will likely need an adaptor bracket or hole modification Also note that all new replacement coils for Onans are non threaded for spark plug wires. We recommend swapping out your wires if you do have threaded wires boot ends, and it is also a good practice to swap them out when you change the coil anyway. There is an option at check out to add wires to your coil order.