Outdrive or coupler fail ?

[Peter P]

Hello forum,

We have a 2008 SeaRay 195 4.3L MPI with Alpha One outdrive.

Putting it back in the water after winter storage the engine runs fine but in drive it hesitates and does not come up to speed.
After a while the boat drives fine, driving around 2000 rpm we feel a big clunk, as if we hit a piece of wood..
Boat slows down, impossible to get it back up to speed with engaged drive.
We can luckily limp back to port at very low speed, speedometer stays at 20 MPH even at this speed.
No damage to the propellor.

Does anyone have an idea what could be the cause?

Thanks for your advice,

Peter

 

[b_arrington]

If it were a coupler, you would not get any speed at all. When a couple goes it lets go all the way. Seems like perhaps a spun prop hub?

the stable speedo seems weird. Those are usually a pitot tube that sense water pressure to display speed.

 

[scoflaw]

"Big clunk" sounds like the drive. Couplers can fail in the exact same way a rubber hubbed prop fails , acts like a slipping clutch. Rubber separates from the metal.

 

[Peter P]

If it were a coupler, you would not get any speed at all. When a couple goes it lets go all the way. Seems like perhaps a spun prop hub?

the stable speedo seems weird. Those are usually a pitot tube that sense water pressure to display speed.

Thanks Brad for the info, will check to see if there is an issue with the prop hub early next week.

 

[Peter P]

"Big clunk" sounds like the drive. Couplers can fail in the exact same way a rubber hubbed prop fails , acts like a slipping clutch. Rubber separates from the metal.

Hoping it is the drive, seems like the lesser costly repair in hours of labour

 

[Strecker25]

There’s an off chance it’s the prop hub, we had something similar on the 290. If it’s the flo-torque hub you can mark it’s position with a paint pen and go for a ride then recheck it

 

[Bt Doctur]

Flo-Tork is plastic and will break ,you may or may not have any prop effect depending. Remove the prop and check, it will be obvious. There is a res oil bottle on the port side ,front of engine , any oil in it?

 

[Lazy Daze]

A spun hub or bad coupler will equal high engine rpm with little movement - kinda like driving your car with your foot half way on the clutch. Since you didn't mention anything about oddly high RPM for the speed, these wouldn't be the issue.

You can check propeller engagement by hand in N-F-R. Listen for odd engine sounds in neutral and in gear.

You could have a couple things going on - bad gas, needing a tune-up... and possibly a mechanical issue to explain the clunk (or, again, actually hitting something). Gonna be hard to diagnose over a forum with limited info - will be mostly guessing.

As Brad pointed out, the speedo is a totally different (easily fixed) thing and in no way related to the problem... other than if you did hit a big chunk of wood and it clogged the pitot hole.

 

[Peter P]

Really useful info here, many thanks, will check in the next days !

 

[Soulshine]

Agreed on the coupler being an all or nothing fail.

A sure sign of coupler failure is no propulsion immediately followed by overheat since your raw water pump is in the drive.

If the coupler fails, the drive stops turning. No prop rotation, no incoming raw cooling water.

I like the idea of marking the prop to see if the hub is slipping. A spun prop hub will allow you to limp home.

 

[Peter P]

Checked the prop hub as this is an easy thing to do.
No loose plastic bits, but I was surprised it fell right out.. was full of grease/water, but it looked OK..
Pitot tube was blocked by shreds of wood so surely must have hit a log while on plane (we drive on a canal with lots of commercial traffic..)
Will check noise on drive with engaged gear..

 

[BillK2632]

What you described with the torqflo hub is normal - mine typically just falls out of the prop when I remove it. As far as the shifting, when in N the prop should spin freely in both directions. In F it will click when turned clockwise and lock when turned counter-clockwise. Should click/lock opposite in reverse.