72C Velvet Drive freewheel in Neutral

[Unchained]

Hope everyone is doing well. Hey Bob D., I saw your youtube video on this exact same issue. What did it end up being?
Has anyone else experienced this? I'm guessing at least two of the forward clutches are stuck together or one is warped a little and grabbing on to the next one? I just had it rebuilt two seasons ago too.
Let me know. Thanks.
Mike

[prowlersfish]

In mosts cases its normal clutch drag , nothing to worry about . Some do it some don't . The less drag on the shaft the more likly for it to happen .

[BobCT]

Mike,

Mine did turn out to be a couple of warped clutches, I just rebuilt it last week. I noticed this season that I had to bump the shifter into reverse 1-2 times while the boat was being untied. Not a big deal but when I winterized a few weeks ago, the prop was spinning like crazy without any water drag.

My clutches actually looked great but a couple had a noticeable spring when I put them on a flat metal surface. The rebuild was a little trickier than I thought mostly because the manual I had didn't have any disassembly instructions. There are a couple of steps (separating the pump housings with air) that are not the least bit obvious. My plan was to bench test it by welding up the old damper flange (which I did) to a drill or AC motor. What I found out is that this will work for a trans w/o a reduction gear but the one you and I have has too much drag. I could maybe get 50 RPM's and then the motors got hot. So, I drove it down to Mack Boring in NJ and they bench tested and re-adjusted the clearance on the clutches for me.

I think a better approach for you guys that want to do this yourself would be the following:

Pull the trans and do the rebuild (seals, gaskets) and send the "ring assembly" to a rebuilder to replace the clutches. This is the step that requires some knowledge and a press. I have the press but not quite all the knowledge

Everything else is easy and by doing it this way it becomes a manageable size part to ship or drop off somewhere and maybe they charge you an hour labor. Specific to the mid cabin, you'll need to remove the aluminum decks supports and crossmember and disconnect the exhaust hoses from the muffler end. Once you do that there is pretty good access to remove the transmission. I replaced the damper while it was out. Overall, I'm not too concerned about my other trans because the seals and gaskets were in great shape.

Bob

[prowlersfish]

Before you go pulling a trans remeber some clutch drag is normal , depending on how tight the clutch pack is . Most the time nothing to worry about .They seem to do it more cold some times Even slightly warped plates would be no big deal . I have seen many pulled and "fixed" only to have the same issues .

Now it its moving the boat alot then it maybe a issue . Being very careful try and stop the shaft with a peice of wood , it it stops your fine as most likely all is in spec. if you boat moves along at 4 knots in neutral then you may have a issue .

FWIW I have built many of these over the last 30+ years

[prowlersfish]

Before you go pulling a trans remeber some clutch drag is normal , depending on how tight the clutch pack is . Most the time nothing to worry about .They seem to do it more cold some times Even slightly warped plates would be no big deal . I have seen many pulled and "fixed" only to have the same issues .

Now it its moving the boat alot then it maybe a issue . Being very careful try and stop the shaft with a peice of wood , it it stops your fine as most likely all is in spec. if you boat moves along at 4 knots in neutral then you may have a issue .

[Diverted Income]

Was going to ask this very question myself. STBD trans is always turning the prop shaft. Shifts fine but in neutral it still spins the shaft. If you are, say floating in a lock trying to maintain position, it always takes a few reverse jabs to stay in position. It is certainly enough to move the boat. Cause for concern or just add it to the list?

[Big D]

Really depends on how much slip if any there is on the plates. Paul's suggestion with the wood is good. Use a 2x4. It shouldn't take much pressure to stop the shaft. If you find you can't stop it from turning with a little pressure, then it's something to add to the list.

[Unchained]

Thanks for the input guys. I could get up to a few knots just in neutral and it makes docking a challenge sometimes, although I learned to compensate for it quite well this past season. I had to keep water pouring onto the shaft and cutlass bearing too when winterizing. Without any drag, it spins at close to the same RPM's as the engine. It only takes about an hour or so to pull it, so I guess that's going to be my plan.
Mike

[prowlersfish]

If your getting a few knots of speed it could be a issue . But even a perfect gear will have a slight clutch drag and will spin the output shaft with no load . Many cases the packing and cutlass have enough drag to stop the spinning . The 2x4 test can determine if its excessive .

Possible causes of the spinning .

slight spinning - normal ( stops easily with the 2x4 ) Shaft would be spinning slower the eng speed ( Compare neutral to forward )

Excessive spinning Causes :

Warped clutch plates

Internal leaks of the control valve control Hyd circuit

Clutch pack to tight ( due to Assembly )

Bushing seizing binding between 2 internal shafts ( rare)

If I seem negative on doing a repair , I just what to make sure you have a real problem and not something normal .

[BobCT]

Mike,

That's exactly what I had to do with mine, spray the cutless bearing to winterize.

Bob