shaft ejected underway |
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commando
Newbie Joined: April-22-2018 Location: Tennessee Status: Offline Points: 4 |
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Posted: April-22-2018 at 3:17am |
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Hello CC world. I'm looking for advice from the vast experience displayed here: in short; 1980 ski nautique, 1:1 velvet drive- bilge flooded while underway and rag floated up and got caught around the output coupling causing instant lock up of transmission. The result was an ejected shaft and a stalled motor. I put it all back together and motored back to the dock. I now hear a high pitch whine. Does anyone have some insight to what I may be looking at when I pull the drive and tear in to it? Should I go ahead and order a clutch set?
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 10726 |
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What was the rag, a kevlar reinforced beach towel or something?
But anyways, welcome to CCF. If your shaft came out of the coupling and slid backwards, you have some definite issues here. That's normally an interference fit meaning you have to heat the coupling to 500 or so degrees to be able to slip it on the shaft, (unless you have one of the newer double tapered shafts) Since you put it back together out on the water you're either really, really strong or the fit between the coupling and shaft is very loose. I'd guess it's the fit being bad. It's never a good thing to be able to slide the coupling on by hand Since you could drive it back, you at least know the transmission works but whether it's 100% who knows. You'll need a new shaft and coupling due to the loose fit They can develop this loose fit over time due to bad shaft alignment. Don't know what the high pitched whine is but it could be from the slop between the coupling and shaft while it's rotating. How's your prop? It probably hit the rudder when the shaft came out of the coupling unless you had a collar on the shaft in front of the packing gland nut to limit how far it could move. |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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Frank,
Ken is spot on and yes, you have a problem. The damage to the shaft and coupling is called fretting and caused by bad shaft to engine alignment. The boat has been run for some time without the maintenance of alignment. You will need a new shaft and coupling. Most will go with a A.R.E. shaft system since it's double tapered, it eliminates the more complicated assembly of the heat shrink coupling. Don't get tearing into the trans yet. I, like Ken feel it's OK since you drove the boat. I'd say the noise is coming from the shaft stuffing box because the shaft sliding aft disturbed the packing. When was the last time you performed an alignment? One cause of shaft misalignment is rotten stringers. Since your CC is an 80, I'd suggest taking a close look. Welcome to CCfan. Tell us more about the boat and we do love pictures. |
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Duane in Indy
Platinum Member Joined: October-26-2015 Location: Indiana Status: Offline Points: 1578 |
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Unhook the shaft coupler from the trans and see it the shaft is binding or stiff. The trans could be run then at that time. Although no load would be on the trans you may be able to detect some noise. If the rag was dragging the trans down before it locked it up then it is possible you have a clutch issue. Just need to start diagnosing each part of the drive train
.Good luck |
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Keep it as original as YOU want it
1978 Mustang (modified) |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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Carbon fiber and Kevlar? I feel Frank will find the noise is from the packing gland. Duane, I've been there! |
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Duane in Indy
Platinum Member Joined: October-26-2015 Location: Indiana Status: Offline Points: 1578 |
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I have to agree that the packing gland could be the culprit. IF the rag happened to grab the nut and spin it tighter then that could easily be the problem. Anyway taking the shaft loose should tell a lot. edit: but would the trans have to be in reverse to tighten the nut?? |
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Keep it as original as YOU want it
1978 Mustang (modified) |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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Duane, I don't feel the packing nut would need to be tightened to make the squeal. It doesn't take much to make the noise. I chased it on my X55 for almost a whole summer. Making the noise is ether:
Or; Frank may have not gotten the shaft all the way into the coupling so the packing rides on a different spot on the shaft. |
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commando
Newbie Joined: April-22-2018 Location: Tennessee Status: Offline Points: 4 |
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Thanks all for your input. The "rag" was an oil absorbent pad, placed under the transmission to collect the leakage. Pure negligence on my part not monitoring the bilge level and it floated up and got caught in the coupling. It put up a good fight because there were shredded pieces of the pad everywhere. The prop damage was a small dent in one blade, repairable. As easy as it was to re-fit the shaft, wear is definitely an issue. I haven't yet had a chance to investigate the engine/shaft/strut alignment. I work away from home and plan to tear into next week when I get back. I've already ordered a rebuild kit for the transmission, its leaking bad so it was on my list of projects anyway and I like to tinker. Most likely I will be replacing the shaft and will go with the double taper.
I bought the boat under the "next project" premise. Stringers are visibly/hammer tap sound but they have made a fool of me before. There is an aluminum frame bolted to the stringers, the engine/transmission bolted to the frame. I'm not sure if that is factory or a previous owner's attempt to shore it up. I will know more in the near future and will gladly share what I find. Asking for help here is the smartest move I've made so far! Thanks again. |
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shierh
Gold Member Joined: April-29-2015 Location: Florida Status: Offline Points: 605 |
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Aluminum engine cradle is likely standard.
also I don't think oil pad was the culprit. no way that disposable diaper would have removed your shaft. Suspect that the shaft coupling had prior issues such as bolts not tightened into the dimples in the shaft. |
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KENO
Grand Poobah Joined: June-06-2004 Location: United States Status: Offline Points: 10726 |
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From his first post, this might tell ya something |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41040 |
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Steve, If you have ever seen a fretted coupling and shaft to the point where the shaft can slide aft, you will also see that the "safety set screws" will also be pounded out to the point of not holding. It's the reason safety set collars on the shaft have become popular. |
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commando
Newbie Joined: April-22-2018 Location: Tennessee Status: Offline Points: 4 |
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The oil pad was actually about 8 feet long. It came off a roll, like paper towels just exponentially more durable. It was a continuous section folded and folded to make a mat. I had it wedged under the transmission and held down by the freshwater intake hose that routed under there. When it floated free I can only imagine that the coupling caught an end and wrapped all 8 feet around itself before giving up the ghost. It was tightly bound around the output coupling. I also had never checked the set screws to see if they were seated and tight either, most likely a combination of the two screwups got me in to my present situation.
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