I'm not sure if this will help but here are some things I found for you.
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My Pace mower has a Kirby Lauson PLV30 4 stroke motor.
Now you said it has a PLV30 on it but my Victa green book refers to it as having VK30.Which in the illustration below is the model 16R.So are you sure that's what it has on it? If so it may well be,not the original engine.