Does the crankshaft spin? If not maybe there's a dead spot on the flywheel teeth (broken tooth?) otherwise it'd have to be the chain, or the starter is indeed not engaging the flywheel at all....would be a bad starter bendix.

You can verify engine-functionality by rotating it clockwise with a 22mm wrench on the P/S pump nut.....if everything moves its probably fine.

Also, if it were a bad chain, and the starter were spinning the rest of the engine, it'd not sound good, because you'd be hitting valves as the pistons came up....which is why I bet the problem is the starter, not the engine.

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