no prop?

[CampionGuy]

Thanx for reading this post, I hope to find some guidance.

I ran into some grief today during my seasonal inaugural trip.
Here's my setup:
21' Campion Discovery
3.7 L mercruiser (don't laugh, it's worked till now, LOL)
Alpha1 leg with a SS prop.

Today I took the boat out for it's first run of the season and it ran great...to a point.
After a warm up run for 15 mins or so I took it up to 3800 rpm and it was running fine. Ran it up to WOT at 4000 rpm's, ran it there for about 5 mins and then suddenly then the prop sounded like it spun freely as though it was cavitating. Backed off the throttle to idle, ran it up to 1500 to check, all was good. Anywhere above 1500 it sounds like it's free-spinning (or cavitating is how it sounds). Made it back to port (8 miles) at 1500 rpm and pulled the boat. No obvious damage to prop. Didn't hear anything hit the leg in transit.

Have I spun the hub or could it be something more serious?

Thanx in advance,
CampionGuy

 

[Howard Sterndrive]

Re: no prop?

Have I spun the hub

Hopefully it's just the prop.

It's usually quicker to throw another prop on and go for a run than it is to speculate on coupler failure or other possibilities so try the spare prop first.

 

[droptheline]

Re: no prop?

WOT for 5 minutes? with a 470??? no wonder you have problems, id start with your back up prop if u got one and go from there, maybe pull the cap off your upper unit and see how the gears look, i blew an upper last year and limped back to port with symptoms much like yours.

 

[Bondo]

Re: no prop?

Ayuh,.... Change the Prop,.... If that don't fix it, you need a coupler...

 

[ziggy]

Re: no prop?

scribe a line on the propshaft and the prop, in line with ea. other. run it. if the lines ain't lined up no more after the run. spun prop... or try another prop..

 

[CampionGuy]

Re: no prop?

Thanks for the replies guys. I'll take a shot at it today.
Hmmm, I know that spare prop is around here somewhere.

 

[Alumarine]

Re: no prop?

Not that this is your problem but is WOT for that engine only 4000?

If it's supposed to be higher you might want to reprop once yoe figure out what your problem is.

Good luck.

 

[CampionGuy]

Re: no prop?

OK, so I pulled the prop and in behind it I found licorice gummy worms and coffee grounds...seems someone had a little party in there. See pics attached.

So, I am assuming the hub has spun but have no idea why.
Do they wear out over time or is it likely I hit something?
As stated in OP, no obvious damage to the prop.


Found my spare prop but won't be able to get back in the chuck till the weekend.

Thanx in advance,
CampionGuy

 

[CampionGuy]

Re: no prop?

So, I am assuming the hub has spun

Ummm, just to clarify....that was a question.
Dangit, I gotta learn how to phrase things better.
Is that shrapnel and mess behind the prop the kind of thing that happens when a prop is spun?

Sorry for not being clear, I really appreciate the input here.

Thanx in advance,
CampionGuy