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Discussion Starter #1
I've noticed that when I put a strain on my engine, I hear a strange sound. It sounds like a slight screeching/scraping sound. It's not very loud, but it still concerns me. It happens when I put the prop under considerable strain. For example, if Im moving forward and throw the engine in reverse. Or, if I power forward from stand still. I'm worried that the engine Is twisting because of the torque and possibly flexing the shaft. Could the shaft be putting too much pressure on the cutlass bearing because of this? Would the engine temporarily misalign under the load?
 

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Barkeep - Sailor's Pub
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1,951 Posts
Oh .. I know this one!

I know this one .. I've had it before...

Well something pretty close. This is what I did to repair.

First I installed one of these...



then.. these...



Then... this is where the tricky bit came in.. I started with installing this in the first pic....




But... to really make it go away.... I had to adjust the ...



Unfortunately.. that didn't do the whole job... so I needed to go to one of these... in replacement from the Mozart model above...



So now.. whenever I go on my boat. All of this automatically starts up and I don't hear any problems with the engine whatsoever.

you wouldn't believe what it fixed...! The noise from the neighbor's boat? Went away. The loud flapping of the big white things? Gone.

>>>>>>>>>>>>>>>

Slight Schreeching or scraping.... Have you checked the transmission? I guess the shaft could deform under load... and cause it.. so the bearings would be suspect. But I'd also dive into the tranny. What does the fluid look like?

I'm sure others will have better suggestions. (Hope you weren't offended by my post. Just a bit slow around here lately...) HAPPY NEW YEAR! :D :D :D
 

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If Rammstien doesn't work, then you may need to look for the cause. It could be a number of things. Take the engine cover off and with a flashlight try to see what's out of the ordinary - excessive movement, for example. Once you know that and post it here, it will be easier to help with a diagnosis.
 

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Anything-Sailing Founder
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2,241 Posts
DUDE!!! I didn't know you had the Rammstein model. It Freaking Rocks!!!




I know this one .. I've had it before...

Well something pretty close. This is what I did to repair.

First I installed one of these...



then.. these...



Then... this is where the tricky bit came in.. I started with installing this in the first pic....




But... to really make it go away.... I had to adjust the ...



Unfortunately.. that didn't do the whole job... so I needed to go to one of these... in replacement from the Mozart model above...



So now.. whenever I go on my boat. All of this automatically starts up and I don't hear any problems with the engine whatsoever.

you wouldn't believe what it fixed...! The noise from the neighbor's boat? Went away. The loud flapping of the big white things? Gone.

>>>>>>>>>>>>>>>

Slight Schreeching or scraping.... Have you checked the transmission? I guess the shaft could deform under load... and cause it.. so the bearings would be suspect. But I'd also dive into the tranny. What does the fluid look like?

I'm sure others will have better suggestions. (Hope you weren't offended by my post. Just a bit slow around here lately...) HAPPY NEW YEAR! :D :D :D
 

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Cavitation at the prop at moments of acceleration or chage in prop direction can cause such a noise and have nothing to do with the engine. Continuous cavitation can damage the prop, but if it only occurs at the moments you describe it may have no consequence. Station a crewmember at the stuffing box and see if they can determine if the sound is forward of them at the engine or aft at the prop. 'take care and joy, Aythya crew
 

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Anything-Sailing Founder
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2,241 Posts
Does it sound like a belt slipping or something? That's the only thing I could think of that would cause a screeching noise unless maybe you need to have the stuffing box repacked.
 

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Telstar 28
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As CP has said—IT WOULD HELP IF YOU MENTIONED WHAT BOAT< ENGINE AND TRANSMISSION YOU HAD when asking for assistance like this. Some engines, transmissions, and boats have known issues that are fairly common....and knowing that information makes it a lot easier to answer your question. It would also help if you said where the screeching/scraping sound is coming from.

BTW, yes, the engine can become misaligned under load since the torque put out by the engine is significant. IF you have a broken engine mount, that could allow the engine to move under load.

YOU REALLY SHOULD READ THE POST IN MY SIGNATURE, since you can't seem to figure out that more information in a post asking for help is generally better than less.

I've noticed that when I put a strain on my engine, I hear a strange sound. It sounds like a slight screeching/scraping sound. It's not very loud, but it still concerns me. It happens when I put the prop under considerable strain. For example, if Im moving forward and throw the engine in reverse. Or, if I power forward from stand still. I'm worried that the engine Is twisting because of the torque and possibly flexing the shaft. Could the shaft be putting too much pressure on the cutlass bearing because of this? Would the engine temporarily misalign under the load?
 

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Barkeep - Sailor's Pub
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SD

I kinda liked my answer better. It was nicer and at least fixed his problem! :D :)
 

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JR...

Start your motor, and get your other half to reproduce the symptoms, however you do it.
Go round the motor listening carefully until you get an idea of where it's coming from.
Screeching is normally a belt drive issue, but it should not happen to the alternator belt if the batteries are well charged.
Check the belt tightness.
Which motor is it? Do you have a picture or a reference?
Is there enough lube in the gearbox? Sometimes a 'box can make a funny noise going on and off load.
Generally, if it is not a clattering, the motor should be fairly sound.
 

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Anything-Sailing Founder
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JR...

Start your motor, and get your other half to reproduce the symptoms, however you do it.
Go round the motor listening carefully until you get an idea of where it's coming from.
Screeching is normally a belt drive issue, but it should not happen to the alternator belt if the batteries are well charged.
Check the belt tightness.
Which motor is it? Do you have a picture or a reference?
Is there enough lube in the gearbox? Sometimes a 'box can make a funny noise going on and off load.
Generally, if it is not a clattering, the motor should be fairly sound.
That's pretty much what I was thinking. I don't know of anything else that would make a screeching sound. I would definitely check to motor mounts. Also look around the pullyes on the front of the engine, is there anything in close proximity? Does it show wear that might be cause by rubbing against a pulley?

And as others have said, details of the engine and driveline would help as well.
 

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Retired and happy
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On the basis that diagnosis involves eliminating the simplest possible causes first, then I would agree with those who advocate checking drive belts. If the alternator belt is the cause, then you should be able to reproduce the noise by starting with the engine at a fast tickover with no batteries connected, then switching in both batteries. The charging load on the alternator should result in a screech from the slipping belt.....

Good hunting

Stuart
 

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Irrationally Exuberant
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Man, JR...., I have to go with Sailingdog & Cardiac and say, give some information, for crying out loud! It's not like everyone is right there in the boat with you.
 

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Retired and happy
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We're still talking about a boat problem, right? :)
I'm really glad someone else picked this up. I cracked up reading it (no offense, Rockter) assuming it related to some form of mating ritual. Though, I must admit, " 'box" is not a term I am familiar with in this context.......:)

Stuart
 

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Anything-Sailing Founder
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2,241 Posts
I'm really glad someone else picked this up. I cracked up reading it (no offense, Rockter) assuming it related to some form of mating ritual. Though, I must admit, " 'box" is not a term I am familiar with in this context.......:)

Stuart
OMFG. I just picked up on that one.


Anyway, as for the switching the batteries in and out. You really should be careful. Most alternators I know of are likely to blow the regulator if you disconnect the batteries while the engine is running.
 
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