Every once in awhile I get a loud noise that sounds like it is coming from the prop shaft area. When I reduce RPM's the noise goes away and may not be heard for quite some time. I have a new prop shaft, PSS system and new cutlass bearing and the problemn persists. I have burped the system also to no avail. Any suggestions please post on the forum and email to rbonomo1@msn.com. Thanks, Rob
Prop Shaft Noise
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Vibes
Rob Engines and all the stuff that comes with them have "resonating" frequencies which changes from both time to time and with changes in hardware. Unless I miss your question, at some time during the acceleration from 600-800 rpm idle to full throttle for cruising at 2600 rpm or higher at 2700 - 3000, you are GOING to have things vibrating differently. If that's all you have, it COMES WITH THE BOAT. Our 'good' rpms are 1100, 1500 and higher. Anything lower than 1500 unless the 1100 is weird and wobbly. Maybe that's what we should name our next boat: W&W!!!!! If not, please be more specific with your description, although, quite frankly, it's impossible to feel a vibration through the Internet.
Stu
Rob Engines and all the stuff that comes with them have "resonating" frequencies which changes from both time to time and with changes in hardware. Unless I miss your question, at some time during the acceleration from 600-800 rpm idle to full throttle for cruising at 2600 rpm or higher at 2700 - 3000, you are GOING to have things vibrating differently. If that's all you have, it COMES WITH THE BOAT. Our 'good' rpms are 1100, 1500 and higher. Anything lower than 1500 unless the 1100 is weird and wobbly. Maybe that's what we should name our next boat: W&W!!!!! If not, please be more specific with your description, although, quite frankly, it's impossible to feel a vibration through the Internet.
Stu
vibration
There was a thread a year or two ago about a shaft vibration. I have a cat 30 with a pss seal which I love but I think it contributes to the resonance at some rpms as it does not support the shaft like a "normal" packing. thry looking up PSS seal and vibration in the archives. I hadn't had any vibration for over a year then just last week it "buzzed" - sounds like someone is rapidly tapping the hull - I suspect it is the drive shaft vibrating and touching the hull exit shaft hole.
There was a thread a year or two ago about a shaft vibration. I have a cat 30 with a pss seal which I love but I think it contributes to the resonance at some rpms as it does not support the shaft like a "normal" packing. thry looking up PSS seal and vibration in the archives. I hadn't had any vibration for over a year then just last week it "buzzed" - sounds like someone is rapidly tapping the hull - I suspect it is the drive shaft vibrating and touching the hull exit shaft hole.
Reply to Stu.
Thanks for your reply Stu. I actually get very few vibrations through almost all power settings. The loud and sudden vibration I am speaking of usually occurs while moving through choppy waters and comes on very suddenly. I also have to say that it has occured in calm waters but not as often. It almost sounds as if the pro shaft is vibrating in the cutlass bearing but I have replaced both. This sound is a very loud vibration and spinning sound. Thanks for any thoughts.
Thanks for your reply Stu. I actually get very few vibrations through almost all power settings. The loud and sudden vibration I am speaking of usually occurs while moving through choppy waters and comes on very suddenly. I also have to say that it has occured in calm waters but not as often. It almost sounds as if the pro shaft is vibrating in the cutlass bearing but I have replaced both. This sound is a very loud vibration and spinning sound. Thanks for any thoughts.
Try Tom Soko
Rob We haven't had this kind of thing come up with the C34s. Try Tom on your C36 Assoc website, he's very good. I had a small problem a few years ago, where my shaft key fell out! No one believes me, but it did. I now have it cable tied into place. Any little thing can throw it off. Have you checked your alignment? Are all the bolts tight on the coupling? The list goes on.... Good luck, Stu
Rob We haven't had this kind of thing come up with the C34s. Try Tom on your C36 Assoc website, he's very good. I had a small problem a few years ago, where my shaft key fell out! No one believes me, but it did. I now have it cable tied into place. Any little thing can throw it off. Have you checked your alignment? Are all the bolts tight on the coupling? The list goes on.... Good luck, Stu
Same Problem Fixed
I had what I used to refer to as a gremlin. I'd be motoring and without warning a strong vibration under my feet. Everyone on the boat could hear it and it was a bit frightening. Lowering revs stopped always it. I had many friends come out with me and we'd try to make the vibration occur, but it never did when someone was watching. I eventually called the prior owner and he said it is a simple fix and the vibration caused by the dripless seal. He (and the company) told me to get 600 or 1000 grit sandpaper, fold in half and rub it a circular fashion around the shaft between the plates of the dripless seal. (PYY said toothpaste also works). I later swapped out the older model dripless seal (the one with no water tube) with a newer one (with a water tube) and have never again had the problem.
I had what I used to refer to as a gremlin. I'd be motoring and without warning a strong vibration under my feet. Everyone on the boat could hear it and it was a bit frightening. Lowering revs stopped always it. I had many friends come out with me and we'd try to make the vibration occur, but it never did when someone was watching. I eventually called the prior owner and he said it is a simple fix and the vibration caused by the dripless seal. He (and the company) told me to get 600 or 1000 grit sandpaper, fold in half and rub it a circular fashion around the shaft between the plates of the dripless seal. (PYY said toothpaste also works). I later swapped out the older model dripless seal (the one with no water tube) with a newer one (with a water tube) and have never again had the problem.
Vibration
Am I the only one who thinks that Stu Jacksons replies are mostly demeaning and condesending??
Am I the only one who thinks that Stu Jacksons replies are mostly demeaning and condesending??
Doug, in one word - YES -
You are the only one as far as my opinion goes. Stu has a great depth of knowledge, which he shares. I thank him. If you find his comments condecending and demeaning, take up golf.
You are the only one as far as my opinion goes. Stu has a great depth of knowledge, which he shares. I thank him. If you find his comments condecending and demeaning, take up golf.
Propshaft Noise
Rob; When you say "I have burped the system also to no avail", do you still get the noise on that outing, or on another outing say a week later? I get a noise somewhat like you are describing with my PSS dripless. It requires a burp to get rid of, but my neighbor is always checking zincs with his scuba gear on, and a stray bubble will go up inside the the seal. So ocaisionally I need to burp my PSS.
Rob; When you say "I have burped the system also to no avail", do you still get the noise on that outing, or on another outing say a week later? I get a noise somewhat like you are describing with my PSS dripless. It requires a burp to get rid of, but my neighbor is always checking zincs with his scuba gear on, and a stray bubble will go up inside the the seal. So ocaisionally I need to burp my PSS.
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