Dual Engine; Finding Crankshaft Horizontal Center Line (X-Dimension) - Mercury MerCruiser 3.0 MPI Installation Manual

DRIVE SYSTEM AND ENGINE INSTALLATION
2. If unknown, a compass can be used to locate the vertical centerline:
a.
b.
c.
b
a

DUAL ENGINE

1. Locate and mark the vertical centerline on the transom. Refer to Single Engine procedure.
2. Make a set of marks equal to 1/2 the minimum distance between crankshaft vertical centerlines
on either side of the vertical centerline
Model
181 cid / 3.0 liter
3. Draw the 2 crankshaft vertical centerlines through the intersection of the marks.
b
Finding Crankshaft Horizontal Center Line (X‑dimension)
X‑dimension can be measured by the 90 Degree Tool Method or by the Tape Measure Method.
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Mark identical locations on each side of the boat 29.4 cm (12 in.) from the bottom of the
hull.
Position the fixed end of a compass at the marks and draw arcs on the transom.
Draw the crankshaft vertical centerline through the intersection points of the 2 arcs.
e
c
d
Single engine installation
a - 29.4 cm (12 in.)
b - Identical side marks
c - Compass arc
Minimum Distance Between Crankshaft Vertical Centerlines (Dual Side‑By‑Side)
b
a
Dual installation
a - Vertical centerline
b - 1/2 minimum distance between
crankshaft centerline marks
b
d - Arc intersection points
e - Crankshaft vertical centerline
c
c - Crankshaft vertical centerlines
90-899883183 DECEMBER 2007
SECTION - 6
e
7687
cm (in.)
83.8 (33)
c
7688