I want to do a compression test on a 1981 Johnson 70 hp, (never done a compression test on anything) The Clymer manual I have says, do it with the engine warm, well that's the first problem, the engine won't start, so does it really make a difference whether its warm or cold? It also says disconnect the "power pack-to armature plate connector to disable the ignition system" Is this also necessary considering the motor doesn't start anyway? Thanks