503 Single Carb Single Ignition question

[LSaupe 123]

There is a new in box older 503 for sale here locally that I am interested in.  It is a single Bing carb and single ignition.  Anyone know when they started to go to dual ignition?

Any other major changes in the engine over the years to be aware of?  Fair price for such a beast with B box, carb and exhaust?

 

Edited 29 Dec 2018 by LSaupe

[Dusty 126]

Not sure of the change date but later 503 engines  had a heavier crank.the early 503 is nearly indestructible as I doesn't make enough power to hurt itself! The only mod I would reccomend is installing a Nippon denso Cdi  ignition from a snowmobile,as the points need adjusting about every 30 hours which is a PITA,bad points =bad timing = crank problems! My 503 has 1200 hours and has only needed the crank seals replaced. The value here would be the price of the gearbox plus a little for the engine

[LSaupe 123]

Is there an easy way to determine if the engine is CDI or points?  I assume the dual ignition is CDI, but did Rotax make single ignitions in both CDI and points?

[Dusty 126]

All aero engines with single ignition are Bosch points as (if I am correct ) Nippon wouldn't supply their units for aviation use. The snowmobile equivalent  which I can't remember the designation had the Nippon units and they are an easy retrofit.

[LSaupe 123]

Geat info, thanks Dusty.

[Cloud Dancer 69]

All aero engines with single ignition are Bosch points as (if I am correct ) Nippon wouldn't supply their units for aviation use. The snowmobile equivalent  which I can't remember the designation had the Nippon units and they are an easy retrofit.

I seem to remember a company that made dual spark plug heads for those engines at some point and while it had two spark plugs; it was not a true dual ignition system.