Prop Hub Spun?

[JMHuss]

Hello all!<br /><br />I recently purchased a 14' Starcraft aluminum fishing boat with a 1972 Evinrude 9.5 HP Sporttwin. I've taken it out a few times and have had the same problem everytime: it runs fine at slow speed, but when trying to throttle up, the RPM's shoot up and I lose thrust. I've been reading about spun hubs and this sounds like what is happening. What I'm unclear about is: can a spun hub happen to all props, or just the splined versions? Mine has a shear pin that is brand new. If this is not my problem, can anyone suggest where to go next? Also, if this is indeed my problem, what should I expect to pay to have a new hub pressed in?<br /><br />Thanks for any help!

 

[Dhadley]

Re: Prop Hub Spun?

Welcome!!<br /><br />Where is your anti-ventalation plate in reference to the bottom of the keel? How far forward of the transom does the keel actually stop? Is the motor centered on the keel? Not necessairly in the center of the transom, but centered on the keel.

 

[b.gagnon]

Re: Prop Hub Spun?

Disconnect the fuel and run it until it dies. Next pop the plug wires off, put it in gear and try to turn the prop by hand. Watch to see if the prop turns without the hub.

 

[JMHuss]

Re: Prop Hub Spun?

Originally posted by Dhadley:<br /> Welcome!!<br /><br />Where is your anti-ventalation plate in reference to the bottom of the keel? How far forward of the transom does the keel actually stop? Is the motor centered on the keel? Not necessairly in the center of the transom, but centered on the keel.

Thanks for the welcome!<br /><br />The plate is approximately 1 inch below the bottom of the keel. I couldn't really tell on where the keel stopped (it was dark and raining when I was looking), but looked like it runs the whole length of the boat. The motor appears to be centered perfectly in relation to the keel.<br /><br />Thanks again for the help!

 

[JMHuss]

Re: Prop Hub Spun?

Originally posted by b.gagnon:<br /> Watch to see if the prop turns without the hub.

The prop does move slightly without the lock nut (and cotter pin) turning.