The Engine no denotes Mid> Rotomo 2. However the engine is not Rotomo. The 4 denotes Victa 125 model 2a 4 5>. It is my opinion this engine has been stamped incorrectly and should more than likely read either 169244 Or A69244,AC69244 Making it either a model 4 or Model 5 S2. In any case its incorrect for the base it stands on. In saying this,it is also an Unusual sequential numbering error for this period. Good to have in anycase as im always on the look out for errors and the unusual. The engine you require for this mower is a model 2 125 Rotomo engine. Its chassis is model 2 and the use of plastic wheels denote it being in the latter stages of the Rotomo series 2. Correct engine serial would be 75,000 to 100,000. Hope this helps if your planning to restore her to original specs...If not and you wanna keep it how you found it then thats great too...Good luck and enjoy your new find. Anything you need to know Just hit Jonesy or myself up and a few other members who are well versed in early victa history and accuracy of Models...Enjoy