-> On 11-24-95  11:45, George Skinner got back to Dan Ceppa 
 -> The crankshaft usually doesn't matter.  However, a different camshaft
 -> is required.  Often, a different rear main seal is needed.  A
 GS> Dan: Most marine engines do turn anti-clockwise, but not all as you
 GS> have stated. In a boat with two engines usually one will be
Sorry, most all boat motors that have come through the shop have 
been standard rotation for the motor it was based upon.  
 GS> anti-clockwise, so that engine torque does not cause the boat to roll,
The twins are set to rotate in opposite direction, as you note.  
 GS> of pitch on the propeller is also a determining factor. You must
 GS> remember that both camshaft and crankshaft determine the direction of
Most crankshafts do not have offset throws.  As such there is 
usually no need to hange them to a different crank.  However, the 
rods are offeset.  All that is necessary is th mount them 
backwards to get the correct thrust action.  
 GS> correct piston timing, and that is possibly why a different rear main
 GS> seal is used. 
Manny rear main seals are designed to work in a single direction.  
Installing one in a reverse rotation motor can make the seal act 
as a pump to revove oil from the engine.  We found this out the 
hard way when a guy requested a seal and didn't specify that the 
motor was marine, let alone reverse rotational.  
 GS> Most water pumps use a directional vane for pumping
 GS> water, so that either the water pump is replaced or somehow modified so
Again, most water pumps are designed to rotate in a particular 
direction.  The vanes are the key.  Marine pumps are usually 
made to pump in either direction.  Further, they are expoxy 
coated and use stainless steel components.  
 GS> driven. I do think that most fuel pumps are electric, so that engine
 GS> rotation is not a factor.
We still sell a fair share of mechanical pumps.  Often, the 
electrical pumps we sell are secondary emergency pumps.  They 
have to be of a pull-through type and are mounted behind the 
mechanical primary pump.  
... Spinnaker: Device for impressing landlubbers and depressing crews.
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