72 25hp Evinrude: Prop disengaging

[renaldoaoa]

Just got back from a ride and my prop kept disengaging.

While moving the prop would stop turning and the motor would rev higher, but when I would back off the throttle it would start working again.

This happend maybe 10x's. When the prop would kick back in I didnt hear any noise, it just started working.

I took off the prop and everything looks good.

I've put off changing the foot oil, could that have something to do with this problem?

If not what should I start looking at?

Thanks for the help!!

 

[renaldoaoa]

Re: 72 25hp Evinrude: Prop disengaging

Would just changing the oil fix this?

 

[F_R]

Re: 72 25hp Evinrude: Prop disengaging

Is it a smooth disengagement and re-engagement or a violent one? Violent means it's coming out of gear. Smooth means it's the prop hub slipping, or cavitation. To check the prop hub, make a mark on the prop nut and another mark on the propeller, aligned with the first one. Run the motor till the problem occurs. Stop the motor and check the marks. Are they still aligned? No? Then the hub slipped.

 

[renaldoaoa]

Re: 72 25hp Evinrude: Prop disengaging

Its a smooth disengagement.



http://img451.imageshack.us/my.php?image=dcp0005mi6.jpg



Just taking a guess is the hub the black piece sitting on the prop?

Pay no attention to foot oil, I just drained it.

Thanks for the help!!

 

[renaldoaoa]

Re: 72 25hp Evinrude: Prop disengaging

Let me try and correct myself.

The black piece is considered the prop nut? Mark that and mark the prop and if it moves then the hub is slipping.

I could take another stab at what I think the hub is, but Ill let you point it out.

Thanks F_R!!

 

[tashasdaddy]

Re: 72 25hp Evinrude: Prop disengaging

your prop has a outer metal core and a metal inner core, the rubber in between is slipping on the metal. it's probably the original prop. time for a new one or a prop shop can rebuild the existing one. put the prop back on, then take a sharpee and draw a line completely across the hub metal to metal. give it a quick run, most likely the line will not line up when you are through.

 

[F_R]

Re: 72 25hp Evinrude: Prop disengaging

To further explain, the bronze part with the slot for the shear pin is the hub. There is a rubber "donut" bonded to the bronze. Then the whole thing is pressed into the part of the propeller that has the blades. What happens is that the rubber tears loose from the bronze hub, and when it does the hub spins in prop. I think they sell props here at iboats.

 

[renaldoaoa]

Re: 72 25hp Evinrude: Prop disengaging

Gotcha

I appreciate you two walking me through this.

Many thanks!!!!