Got the old clunker on the left for $20 as a source of spare parts for my machine on the right (will have it's 31st birthday in a couple of months). Thought I'd throw a cupful of petrol in it to see if it ran. Was more than a little surprised when it cranked up on the second pull of the starter!
So did a complete disassembly with a good degrease and cleaned everything up, including all the rusty bits. New plug, new throttle cable, changed the oil, cleaned out the rubbish in fuel tank, replaced the silly paper filter on the handlebar with an oil impregnated foam filter and housing, good second hand muffler with a new exhaust gasket, new blades and even splashed on a bit of paint on it where needed.
After reassembly and making some adjustments to mixture and idle screws on the carby, I've found that it actually runs smoother and quieter than the current Rover. The chassis also feels a lot tighter (as in the height adjustment mechanism and wheels). It obviously hasn't had the continuous use that the other machine has had over the last 30 odd years. All I need now is a pair of the lower handle bars that bolt to the deck. They're surprisingly hard to come by (Rover don't make them anymore). The others were cracked and I made the mistake of throwing them out. After that its right to go! So with two mowers to share the load, they should both be serviceable for some time to come.