How many splines are on the early force motors crankshaft 3 cylinders (white)

larryb1963

Cadet
Joined
Oct 25, 2010
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6
The reason I am asking this questions is I met a gentlemen who works in a marina tell me that the early motors had 15 spline crankshaft ? but it was a white motor not black . He said that the crankshaft is the same one used in the later sport jet motor ? 1992 . I researched the part numbers and could not find a interchange but wondering if the part number could have changed in the 1990s . Well im now researching a physical inspection hoping if this might be correct . Thank you for reading this .
 

Frank Acampora

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Jan 19, 2007
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12,004
ALL Chrysler and Force 3 and 4 cylinder outboard engines from the late 1960s on (with the exception of Force 70 and 75 HP) used a 15 spline crankshaft. They only changed when Brunswick changed to a Mercury lower unit. Jet drive engines and L drive engines, being the same engine but different propulsion may have different spline count. Someone familiar with them may chime in here. Some sport jet engines used an oil injection pump driven off the bottom of the crankshaft and these crankshafts are different.

If you are not swapping the special case engines it is safe to say that any three cylinder outboard crank will fit in any three cylinder outboard block.
 

jerryjerry05

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May 7, 2008
Messages
18,075
The jet drive usually had a different crank and a different spline count.
The white and black/blue ​motors, most times the only difference is the color and shape of the cover.
There were some changes in electronics between white and black.
Then Mercury started putting their stuff on in the middle 90's
 
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