From the I&T books I have all MM 4cyls use a 1 3 4 2 firing order. It would be a good place to start anyways.
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UBU-LP, 445N-LP, 445E-LP, Big MO 400-M, 4 Star-LP, M5-D, M5-LP, M602-LP, M670-LP, G900-LP, G900-D, G1000 Vista-LP, Case 580CK, JD 440IC/602, 2-440ICD/831