I attempted to reply to your post Bruce, and I don't know where it went. It's on the site somewhere, so if you stumble across this somewhere, you'll know why:
Novice Registered: 24/12/12
Posts: 10
Loc: Macclesfield, Victoria, Austra...
Thanks all, for your help. The stepped crankshaft is a definite difference from the Masport to the Rover, but that crankshaft drawing certainly looks like mine, although my model no. isn't listed. Mine has a definite shoulder, shown in my earlier photos. I've attached a photo with that detail highlighted from the drawing. Is that the shoulder, or a bearing? Engine details are: Model 130902 Type 1260 01 Code 9109042. I have looked into these numbers online, and see that puts the engine manufacture as 1991.
Another point is that I took the blades to my son yesterday, who is well qualified and experienced in working with steel, and he said the blade material is definitely not spring steel, or even hard. It seems to be mild steel or close to it. That was a surprise,as it looked like spring steel.