Mercury Optimax Models 135, 150, Direct Fuel Injection., Page 268Get this manual
POWERHEAD
13Rotate crankshaft several times (using powerhead stand) to assure free operation (no binds and catching)Connecting Rod Cap Alignment Check each connecting rod cap for correct alignmentIf not aligned, ridge can be seen or felt at the separating line as shown belowCorrect any misalignmentSide View Correct Side View Incorrect-Cap on Backwards End View Correct End View IncorrectNot Aligned End View Incorrect-Cap on Backwards
14Verify that no piston rings were broken during installation by pressing in on each piston ring thru exhaust port using screwdriverIf no spring tension exists (ring fails to return to position), it's likely ring is broken and must be replaced