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minnmarker

What is this noise?

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minnmarker

This whining noise is driving me crazy.  OK, not crazy but it is annoying.

Here's the situation:

Whining noise coming from front of engine.  On the belt side, stern side of V drive.  It is not the fuel pump or an intake whistle.  I took the belt off and it was there as usual, so it is not the alternator or the engine water pump.  On a cold start it takes about 5 seconds for the whine to start.  On a hot start it's there immediately.  It changes pitch just a bit with rpm change.  It is not the Perfect Pass - I disconnected that and the whine was still there.  The raw water pump is not leaking and works fine. Engine runs fine with no issues at all.  2005 Monsoon 340.

 

 

Edited by minnmarker
addition

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minnmarker

Bump. Engine guys, help!

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echie

Its not u blower fan is it?

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minnmarker
1 minute ago, echie said:

Its not u blower fan is it?

Not the blower. Noise starts with engine on and ends with engine off. No noise when cranked with kill switch lanyard off but that's pretty low rpm.

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Dare2goBare

Possibly from the transmission?? Check you oil, Just a thought?

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echie

Maybe check all of ur vacuum lines and make sure a line is not off of the intake somewhere sucking air or a small hole in a vacuum line somewhere..

I personally have never heard that noise from a motor..  So I'm just throwing out ideas at this moment..

Ur transmission full of fluid?  It doesn't sound like a tensioner pulley bearing, but I could b wrong

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minnmarker

I could only find 2 lines.  A crank case vent line with no valve in it that just runs from the valve cover to the flame arrestor.  Disconnecting or plugging it made no difference.  There's another line that looks intact and fixed well at both ends.  It looks like it runs to the intake manifold from somewhere.  Maybe exhaust gas recycle?

The tranny is on the other end of the engine and is filled to the line with nice red Dextron III.

No idle pulley on this engine and the noise was still there after I took the belt off.

Hoping it is not an intake manifold leak.  Any way to diagnose this @Engine Nut or @oldjeep?

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85 Barefoot

if you took the belt off and it was still there, seal in impeller housing?  the one "behind" the impeller?

Edited by 85 Barefoot

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minnmarker
5 minutes ago, 85 Barefoot said:

if you took the belt off and it was still there, seal in impeller housing?  the one "behind" the impeller?

That was one of my suspects as well but it's not leaking.  I suppose the seals could be OK but the bearing could be going bad?  Bakes sells the bearing separately so it's possible just the bearing could go out.

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oldjeep

theoretically you can diagnose an intake leak with an unlit propane torch. The idle will increase is the intake is sucking past the seals. Never done it on a boat though.

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minnmarker
5 minutes ago, oldjeep said:

theoretically you can diagnose an intake leak with an unlit propane torch. The idle will increase is the intake is sucking past the seals. Never done it on a boat though.

When I move my ear side to side and front to back the volume changes but it's hard to pinpoint the source - but it does sound like it's coming from down towards the raw water pump as apposed to under the intake plenum.  I put a screwdriver on the raw water pump housing and could not really pick anything up but maybe it's too high of a frequency to distinguish the source with that method?

It also doesn't change much when I give it some throttle.  Wouldn't an intake leak change tone/volume when opening the butterfly valve?

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oldjeep

you should hear more suck the more throttle you give it with an intake or Tb vac leak

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minnmarker
10 minutes ago, oldjeep said:

you should hear more suck the more throttle you give it with an intake or Tb vac leak

Agreed.  So if it is the raw water pump is it likely the bearing has spun and ruined the shaft and/or housing?  Or can a bearing make that kind of noise internally?

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oldjeep

It looks like you.took the belt off. I'd be lookin at raw water pump bearing or even the impeller spinning on its insert. A bad bearing can make a lot of noise but eventually it siezes and spins in the housing. Also make sure the pump is not flopping from a cracked base.

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minnmarker

Thanks for all the input guys.  It seems like the top suspect is the raw water pump.  I'll just order a new pump.  Not worth my time to try to rebuild especially as I don't know what part of the pump is bad and I don't want to waste a weekend waiting for the right part.

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JasonK

When did the noise start? Was it after an impeller change?

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minnmarker
24 minutes ago, JasonK said:

When did the noise start? Was it after an impeller change?

I'm not sure when it started.  I think it's just gotten worse over time - which points to a bearing going bad - I think.  Impeller was last changed July 2015 with a Johnson OEM and I do not remember the noise being a big issue last year.

All that said, it could just be the impeller so I'll take that out and look at it before I take the whole pump off.  If the impeller looks good then pump swap and I have another spare impeller.

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minnmarker
19 minutes ago, footndale said:

I know the problem, your engine is facing the wrong way. :)

 

North?  It faces North most on the time when on the lift. :rofl:

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Dare2goBare
11 hours ago, footndale said:

I know the problem, your engine is facing the wrong way. :)

 

Lol...Man you kill me.., lol....

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GreenMan

I'd go with the raw water pump. Just take the front cover off and see if there may be a vane missing or some foreign object in there. I think what you hear is the pass frequency of the vanes. If there are some vanes missing you would very likely hear a quite different sound from the pump. Might be able to 'listen' to it with a long bladed screwdriver against the housing and the handle against your ear or something? BE CAREFUL OF THE PULLEYS / BELT!

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minnmarker
4 hours ago, GreenMan said:

I'd go with the raw water pump. Just take the front cover off and see if there may be a vane missing or some foreign object in there. I think what you hear is the pass frequency of the vanes. If there are some vanes missing you would very likely hear a quite different sound from the pump. Might be able to 'listen' to it with a long bladed screwdriver against the housing and the handle against your ear or something? BE CAREFUL OF THE PULLEYS / BELT!

I tried "listening" with a screw driver and a hose but could not pick up anything over the loud whine that fills the back of the engine compartment.  No idea what a pass frequency is???  My plan is to open the pump up and take a look before pulling it out.  Based on the very high pitch I'm thinking metal-on-metal right now, but am not sure.

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minnmarker

Well it is not the raw water pump. Pulled that off the crank shaft pulley and noise was still there! Has anyone else pulled the raw water pump off? What a pain! It was a steel disk in an aluminum hole and had corroded itself in there tight.

So I had someone else work the throttle in neutral (old boats still have that) and the noise would go away briefly when quickly opening the butterfly valve but come right back within a second when the engine sucking air caught up and created a vacuum in the plenum again - which suggests an air leak in the intake. Location of noise suggests the plenum gasket? Could not pinpoint it. I took the plenum off and the gasket looked kind of OK but definitely had some compressed areas and some corrosion on the intake manifold. Ordering a new gasket.

Ideas anyone???

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Big_Moose_Wakesetter
1 hour ago, minnmarker said:

Well it is not the raw water pump. Pulled that off the crank shaft pulley and noise was still there! Has anyone else pulled the raw water pump off? What a pain! It was a steel disk in an aluminum hole and had corroded itself in there tight.

So I had someone else work the throttle in neutral (old boats still have that) and the noise would go away briefly when quickly opening the butterfly valve but come right back within a second when the engine sucking air caught up and created a vacuum in the plenum again - which suggests an air leak in the intake. Location of noise suggests the plenum gasket? Could not pinpoint it. I took the plenum off and the gasket looked kind of OK but definitely had some compressed areas and some corrosion on the intake manifold. Ordering a new gasket.

Ideas anyone???

Just had to chime in because my raw water pump in my 2005 was leaking at the shaft so I replaced it last summer. Mine was corroded as well and I spent over 12 hours trying to get it out.  Tried 4 different kinds of penetrating fluids, prying, beating it with a mini-sledge, etc.  After breaking the pump off the shaft and later the shaft off the base, I finally got it out by cutting the base to pieces with an angle grinder (and a mirror to see what I was doing - except backwards of course!).  I certainly don't recommend that but it got the job done.

Good luck figuring out the source of that whining!

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minnmarker
9 minutes ago, Big_Moose_Wakesetter said:

Just had to chime in because my raw water pump in my 2005 was leaking at the shaft so I replaced it last summer. Mine was corroded as well and I spent over 12 hours trying to get it out.  Tried 4 different kinds of penetrating fluids, prying, beating it with a mini-sledge, etc.  After breaking the pump off the shaft and later the shaft off the base, I finally got it out by cutting the base to pieces with an angle grinder (and a mirror to see what I was doing - except backwards of course!).  I certainly don't recommend that but it got the job done.

Good luck figuring out the source of that whining!

I feel your pain.

For those in the future who may need to know how to get it off.  5/8 open end wrench with big screw driver thru closed end and open end on the shaft and wrench span leveraging against the crank shaft pulley. Penetrating oil applied previously.  Apply pressure with wrench screw driver combo while whacking the pump disk thing with a hammer.  Move it a 16th then rotate a quarter turn with starter and repeat. Then I put it back on! Fortunately it was not bent.

I should have tapped one or more of the extra holes on the disk to create the kind of removal system you see on auto brakes.

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