No spark

I have a 1988 Toyota 2 wheel drive pick up. I was running perfectly and was stored for two years in a garage. We pushed it out and the son put jumper cables on it.. I was gone for 5 minutes or so. I came back and saw he had them backwards. I quickly pulled the jumpers off. Result - blown fuselink under the hood. I replaced the fuselink and the pickup ran great for 3 days or so. It died and now no spark. Replaced cap, rotor, battery. It has a brand new alternator. One strange thing, when you hold the clutch in and you are cranking it like crazy, no spark. When the key is returned to the off position - engine jumps and there is spark for a second. The pickup always ran real nice.

Anyone have any suggestions ? I grabbed another ignition and installed it - still same problem.

Thanks,

David