Spun prop - mark hub question

[81 Checkmate]

Re: Spun prop - mark hub question

I still think a tune up is in order.....Ok say i got a 4 banger that at 4200 rpms is at 110 hp it will run say 35 mph.....then i have 8 cyl that at 4200 rpms is at 190 hp it will run 40 mph.....same rpm....different speed. Comes down to hp......maybe your not at your full hp range at the 4200 rpm. Just saying!

Could be the tach/speedo/pilot tube also like the others have said.

Good luck hope you can find the issue!

 

[bonzoscott]

Re: Spun prop - mark hub question

I think a GPS reading would be my first step. Also haven't considered the tach could be wrong. It shows 800 at idle now but shifts smoothly and doesn't sound high. This is an OMC BTW and no, I don't know the drive ratio. I imagine it's less than 1.5 because it's a V6. The prop is original and "19 pitch. This is what made me post: Everything remains the same except the speed. I'm gonna tune 'er up in the spring and get one of many who have a GPS and check 'er out. For the first ten years, at 4200 RPM would do 50+ MPH. And now my concern is sounds like she's ready to blow at~40 MPH. I thought possibly, a prop lost pitch over the years. Thanks for all the advice.

 

[Texasmark]

Re: Spun prop - mark hub question

I have experienced rubber hub slip from an obstruction on low and high HP engines. The low hp just grunts and resets with you doing nothing. The 125 HP you had to cut the throttle to idle, shift into N, and then go back on your way. Course the times it happened I was well into planing speed. Never lost a hub nor had one changed.

Mark