Hi SimRice,
I would say at a guess your mower would be a late 1960's to early 1970's due to the colour of it. I'd say that it would've had a Kirby Lauson originally fitted and due to it failing at some stage and requiring parts which are pretty thin on the ground it had a later Tecumseh fitted and as Grumpy already mentioned a very bad choice indeed.
The solid deck unit which you have is without a doubt the best issue of the Model 45's as it didn't suffer top deck failure as did the later 45's with the twin rail design and especially on the 20 inch models they failed due to less strength in the rails as they were made from the same thickness of steel as the 14's and 17's were, thus the flexing of the rails was much greater and fatigue failure was on the cards right from the start.
What you paid for the machine is a damm good price (for a 20 inch unit) as once it is completely refurbished both mechanically and cosmetically it'll be in the $1,500 mark region, so all in all not a bad investment at all.
Cheers,
BB
