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Discussion Starter #1
Hi, I have an 1988 Catalina 30 which has been recently upgraded and refitted. Off and on during the last couple of days we are hearing a squealing noise aft,like a loose belt. It seems to come on when in gear over 1200 RPM's.The steering mechanism and gear and throttle cables were just serviced a couple of weeks ago, checked and everything seem OK. Mechanic on vacation until jan 5th. Any ideas? Thanks.
 

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reycuban, if it sounds like belt squeal, probably is. Quick check...while the engine is NOT running, with a rag placed over the alternator pulley cooling fins, try to rotate the pulley. If you can, it's too loose. If not I'd check for misalignment. At any rate, if there is any belt slipage/wear, there is usually some rubber dust from the belt on the surrounding area. Good luck.
 

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Discussion Starter #7
squealing noise

Thanks. The noise is coming from aft, below the binnacle area? The stuffing box was serviced in August, so the cutlass bearing should be OK? I hope.
As I mentioned the noise is off and on and only :confused: when in gear at higher RPM's.
Was planning to cruise for the holidays, should I postpone until mechanic arrives? Thanks for the help.
 

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or...shaft packing too tight? Still, if the belt hasn't been adjusted since replacement and you have around 3/4" deflection(engine manual might have belt deflection limits), I'd give it a tweek. New belts will stretch a bit in the first few hours of use. Just don't over do it, over tensioning is bad on pulley and alternator bearings. There's another source, alternator bearings will sometimes squeal if dry. Might try opening the engine compartment and have a helper try to duplicate the rpm and load while you try to isolate the source of squeal.

Yeah, what Cam and Fred said, jeezh, I type slow!
 

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Discussion Starter #9
Alternator is new,just replaced. Belt is tight,no give. Opened engine hatch while running and no noise from engine, it sounds like is coming from aft. I suspect the cutlass bearing as suggested, but the stuffing box was serviced last August and checked. By the way, the noise is not constant,went for a day without it and goes away if I drop below 1200 RPM's.
Will check stuffing box again, if OK, I think will wait for mechanic. Thanks a lot for the help.
 

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Had that happen on one vessel... Turned out to be a harmonic when the shaft is turning at a low RPM. Check the shaft for straightness and its alignment with the Cutlass bearing.
 

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moderate?
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Reycuban...serviced and checked last august is NOT how you check a conventional stuffing box. It must be continually checked and adjusted to insure that you are getting drips from it when in gear and that the packing is not too tight and heating up the shaft. It may also be that the packing used last August was not appropriate. I suspect you will find the resolution in the packing gland. Make sure it is dripping once every 30 seconds or so when the shaft is turning. If not...loosen the nut a bit!
 

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Maybe something wraped around the prop??
 

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Discussion Starter #13
Thanks

No noise at low RPM's only over 1200 RPM's under load. Suspect prop shaft,cutalss bearing,stuffing box should be OK unless was not properly serviced. I think I will stay close to home for the weekned and use engine as little as possible and deal with the noise when my mechanic returns on the 5th. The Keys can wait for a little longer. Thanks for all the help and suggestions. Happy and Safe New Year!
By the way the weather is great here in Miami for NY's. High 70's,low humidity,sunny,low 60's at night. Winds are light,but OK for NY's Eve on board.
 

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Crazy Woman Boat Driver
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I too have a squeal from down below that has been driving me crazy. I have had 3 mechanics come out to find and fix this thing. Two people are required to do the following.
#1. Thrust bearing on the Transmission - Can test this number of ways. Disconnect the shaft from the transmission. This isolates the transmission from the rest of the system. Run the engine in both forward and reverse. If noise is still there it is definitely coming from the engine/transmission. If noise is gone, now the problem can come from a multitude of places.
a. To test the thrust bearing get a piece of 2X4. Find a place next the transmission coupler to be able to pry against the coupler while the engine is turning ( had a stringer next to mine so I was lucky here). With the 2X4 in place, run the engine and put the transmission in forward gear. Hold the 2X4 up against the coupler to put pressure on the thrust bearing while you power up the engine. If you hear a noise it is the thrust bearing. If no noise, next step.
b. Recouple the shaft to the transmission. This technique will only work on an engine that is on soft engine motor mounts. Get a 1" rope about 3 feet long. Loop rope under shaft between packing gland and transmission coupler. Make sure boat is tied down real good at dock. Start engine and put it in forward gear. When you hear the noise/squeal lift up on the rope and move the shaft around. What this test for is the cutlass bearing, shaft rubbing up against the shaft log and packing glad. The noise should change pitch as you move the shaft around. With a pitch change one should be able to determine where it is coming from. If the noise is caused by the shaft rubbing up against the shaft log or packing gland the engine is out of alignment. If the cutlass is bad the noise will shift to very rear of the boat.
C. If noise/squeal hasn't changed pitch things start to get real complicated real fast. Disconnect the shaft again from the transmission. Slide the shaft either forward or back as far as you can. Don scuba gear because you are going to get wet. Now dive the boat and look at the cutlass bearing and where the shaft would be if the prop shaft was in its proper place. What you are looking for here is Calcium build-up. This happens if the boat has been sitting for long period of time between sailing trips. Also look at the cutlass bearing and see if you can see any build up to prevent water flow through the bearing. If there are deposits on the shaft clean it up with 400 emery paper. Check your zinc to make sure it is not too close the cutlass bearing. Water flow could be inhibited if it is. One should have at least 1/2 inch minimum clearance depending on your boat.
If none of the above works good luck because that is where I am at right now with my boat. At a total lose and frustrated. :confused:
 

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Barking Dog
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Have you burped the dripless stuffing box? No need to pay a mechanic to come and do that. If there is air in there it will squeal.
 

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the pointy end is the bow
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Have you burped the dripless stuffing box? No need to pay a mechanic to come and do that. If there is air in there it will squeal.
That's a fact. We had a PSS Dripless seal that squealed. Took me a while to find the source. Burping it took care of the problem.
 

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Telstar 28
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If the dripless stuffing box is in need of burping, isn't it likely that it may be running dry and doesn't that present a scoring risk to the propshaft???
 

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Barking Dog
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When the boat was serviced a couple of weeks ago, was it hauled at all? You need to burp the dripless stuffing box after every haul/launch.
 
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