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-   -   weird engine noise (http://www.sailnet.com/forums/gear-maintenance/50028-weird-engine-noise.html)

jr438234606 12-27-2008 09:10 PM

weird engine noise
 
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?

craigtoo 12-27-2008 09:43 PM

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...

http://tinyurl.com/95wyvz

then.. these...

http://tinyurl.com/a7m9wg

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

http://tinyurl.com/9k668f


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

http://tinyurl.com/8pp6vy

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

http://tinyurl.com/8w23f4

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

NOLAsailing 12-27-2008 09:53 PM

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.

ckgreenman 12-27-2008 09:57 PM

DUDE!!! I didn't know you had the Rammstein model. It Freaking Rocks!!!




Quote:

Originally Posted by craigtoo (Post 423325)
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...

http://tinyurl.com/95wyvz

then.. these...

http://tinyurl.com/a7m9wg

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

http://tinyurl.com/9k668f


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

http://tinyurl.com/8pp6vy

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

http://tinyurl.com/8w23f4

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


craigtoo 12-27-2008 09:59 PM

Bestrafe Mich!!
Bestrafe Mich!!

Oh. sorry.

ckgreenman 12-27-2008 10:02 PM

Du Hast Buch Dich!!

craigtoo 12-27-2008 10:12 PM

Quote:

Originally Posted by ckgreenman (Post 423336)
Du Hast Buch Dich!!

Ummmmmm
Sorry ..
No.

Funny.
But no.

Du hast...du hast... du hast mich...

CaptainForce 12-27-2008 10:16 PM

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

ckgreenman 12-27-2008 10:30 PM

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.

sailingdog 12-28-2008 07:58 AM

As CP has saidóIT 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.

Quote:

Originally Posted by jr438234606 (Post 423307)
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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