Whatever you do, DO NOT attempt to lever the pulley off the engine. It is cast steel, very brittle, and no longer available.
First thing is to loosen the bolt that is in the centre of the pulley. Undo it 3 or 4 turns.
Next, there are 2 screw holes among the splines. You need to screw some small bolts into those holes and use those as your anchor points for a puller. (without a puller you may never get it off). The centre screw of the puller should run into the centre of the pulley and force against the centre bolt that you loosened.
The final ingredient is heat. You may need plenty of it on the pulley. I used 2 cheap little disposable gas cans with blowtorch attachments in tandem. You can tap on the splines of the pulley with a hammer to give it a little bit of a shock but do not hit the rim.