Starting and maintenance instructions are the same for the 5.5 horse CD-18 model but 1961 was the year OMC made some internal changes on the CD and ten horse QD motors.
The CD’s got needle bearings on the connecting rod big ends that year which allowed the fuel mix to change from 16:1 to 24:1 until 1964 when everything went to 50:1. The QD’s also got the improved connecting rod and wrist pin upgrade that year.
Sorry, no owners manual in PDF but I do have a parts manual for the CD-18.
EDIT: Well, I guess that manual isn’t getting posted until I either figure out how to compress a 2820 KB file down to 2.44 MB or some maximum allowances are changed here.
