Prop Spins Wtin Engine Off and Gear Engaged?

[milkyway]

My rpm was too high so I checked the hub by spinning the prop ( my boat is trailered)manually. I put the gear on forward, the engine is left-handed, but I have not really observed what direction the prop spins. The hub was bad but in the process of doing this investigation, the prop shaft turned freely clockwise ( I was facing the prop) and counterclokwise with some force. Again, the forward gear was engaged. Any comments here? Is my forward gear needing replacement? It is my assumption that the prop shaft would not turn at all under this circumstance. Hope it's not bad news.

 

[milkyway]

Re: Prop Spins Wtin Engine Off and Gear Engaged?

I changed the prop hub and I'm back to 4700 rpm. Recommended rpm is between 4400 and 4800. <br /><br />But is the propeller shaft or that spline where you attach the hub and the prop supposed to turn using manual force by hand ( actually I was using a wrench when this happened) when the engine is off and the throttle in forward gear?

 

[mikecjn]

Re: Prop Spins Wtin Engine Off and Gear Engaged?

With my MerCruiser in gear I can spin it one way freely and it will not spin at all the opposite way. It sounds fine.

 

[milkyway]

Re: Prop Spins Wtin Engine Off and Gear Engaged?

mike,<br /><br />i have the alpha drive, mfd. in 1998.<br /><br />i was able to turn the prop's shaft in "small clicks or increments", as if the shaft was jumping off the gear's teeth. This observation was only incidental to my hub check. I have only 51 hours of boating experience but when I am ready and confident I will remove the lower part of the drive. I will take a look at the forward gear. This gear should be ok since my wot is perfect but may need replacement soon if not later. just trying to have that preventive maintenance approach since nothing comes cheap in repairing boats. thanks.

 

[liner85]

Re: Prop Spins Wtin Engine Off and Gear Engaged?

milky- Don't bother removing your drive. What you describe is normal. Assuming standard rotation, with the drive in forward gear, engine off, the prop should spin freely in the clockwise direction (with some clicking noises). The prop will require quite a bit of force to spin it in the counterclockwise direction, as you will be turning the engine as well (albeit backwards). The gears and clutch are designed to engage each other in one direction but slide past each other in the other direction, similar to a ratchet.

 

[milkyway]

Re: Prop Spins Wtin Engine Off and Gear Engaged?

thanks for sharing your knowledge.