Re: shaft length on a 9.9hp
Up to about 1970, Johnson Model numbers were two or three letters and a two digit number. Prior to 1960 the RD seriers were based on a 40.5 cu-in. block. After 1960 the RD series were based on a 43.9 cu-in. block. The RX series were based on a 35.7cu-in. block, and so forth. Though the number usually identifies the year of production of that model, it is not a calendar year code. After 1970 model numbers include the HP, as in J33ELUTa. J=Johnson 33=HP E=electric start L=long (20") shaft UT=year code (see below) a=production run [After 1980] the year code uses the letters of the word, "INTRODUCES" to represent the digits 1-0. So the UT would be 73. I N T R O D U C E S 1 2 3 4 5 6 7 8 9 0"
