Hi grumpy, great advice there mate, I just went back and had a look at the engine drive sprocket in the pic....It's exactly as you describe, pointy teeth!!
That sprocket can be difficult to remove; I had cause to replace my engine drive shaft and bearing and I had to buy a gear puller to remove it. (Taper shaft and half-moon key)
The gear puller comes in handy when I have to remove the front sprocket for cylinder (reel) removal for sharpening.
