Slack in Crankshaft

[dblanton]

I have a 1981 75hp evinrude and I was curious about possible slack in the crank shaft. When turning the flywheel clockwise by hand the engine feels tight but if I turn the flywheel by hand counter clockwise the flywheel will turn a good three inches before I can feel any resistance (tightness)on the engine. Is this normal or do I have a problem?

 

[DHPMARINE]

Re: Slack in Crankshaft

Turn the flywheel (clockwise) past the tightness.It will probably turn easier,then harder then easier.This is normal.Three inches of slack at the flywheel is pretty much impossible.

DHP

 

[dblanton]

Re: Slack in Crankshaft

Perhaps slack was a incorrect word. I can turn the flywheel counter clockwise three inches past the timming pointer before I can feel any resistance.

 

[F_R]

Re: Slack in Crankshaft

DHP is describing the compression strokes of the pistons as each one takes it's turn moving toward the top of the cylinders. Turning backwards from that point, you would have to wait for the preceeding one to start making it's move upward. Are you sure that's not what you are feeling?

OR, does that engine have a water pump impeller drive key arrangement that allows the shaft to turn backwards a bit without turning the impeller and flipping the blades? I don't know the answer to that question, but that's the story I'm leaning toward at this point.

 

[dblanton]

Re: Slack in Crankshaft

I think you are right about the engine having a water pump impeller drive key arrangement that allows the shaft to turn backwards a bit without turning the impeller and flipping the blades? I can feel the impler blade flip before the pistons begin to move.