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If the engine has external injectors with the heavy steel lines running to them, just loosen the nut at the injector and have someone crank the engine over. You should let it leak out until it start to spurt the fuel out under pressure. If it just bubbles it still has air in it.
If it does not have external lines, then it should bleed itself out. To help one the is difficult, loosen lines up to the engine and away from the engine to help fill them. Again have someone crank it while you loosen the lines one at a time, just wait to see fuel run out before closing it.
I hope this is helpful, I don't have direct experience on New Holland machine but, most work the same.
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