Re: johnson 1951 rd10 motor
Yep RD-10 and RD-11 was introduced in 1951 as a 25hp. Evinrude introduced the Big Twin in that year as well. The 1951 25hp was actually the first motor that Johnson and Evinrude built that was 99% compatable with each other as far as parts interchangeability, thus making it their first corporate motor. 1952, the JW/Lightwins came out in the same concept. By 1956, the whole product line was incorporated.
nwcove, your QD-10 would be the first year of the 10hp Johnson and the first OMC built with the full shift lower unit. Evinrude introduced their first full shift lower unit, in the 14hp Fastwin in 1950. It was infact the same lower unit used on the QD model.
To answer your question deftones2011, yes, tune up parts are available just about every where OMC parts are sold. 1951 and newer OMC motors all shared the same universal style ignition system all the way up till around 1974. Impellers are the same as well. The 25, 28, 33, 35 and some 40's used the same impeller. You should consider buying an impeller as well.