Where can I find a good site that will tell me what motor I have. I have had a heck of a time trying to find a simple list of models with corresponding serial numbers. Mine is a Johnson J50BELCTA, serial number 5810269. I have been told it is a 1983, but I want to know for sure, before I purchase a new lower unit for it. Also I need to know what year a Johnson J50TLERE with a serial number of 03583483 is. Will the lower units interchange? From which years will parts like this interchange?