Screeching from transom area at high RPM's while turning

[mark1905]

1997 Merc 3.0LX, Alpha 1 Gen 2

At high RPMs (4100+), the power steering ram assembly on the transom seems to be making a horrible screeching sound when turning the wheel from side to side. She will be quiet under 4500.

**EDIT - Coming from power steering / drive coupler area.. cannot pin point it.. **

Above about 4400, it screeches constantly.

It started doing it last summer only at very high RPMs while turning, and has gotten progressively worse.. doing it at lower and lower RPMs, and now doing it while not turning but running close to WOT..

Replaced the older PS pump, bled it perfectly. Still doing it.

Not the gimbal bearing, either.. just had that replaced due to a cracked bellow and hence rusty gimbal. It was doing it from before then, also.


Help?

 

[Don S]

Re: Power steering screeching at high RPM's

Re: Power steering screeching at high RPM's

I've never heard one do that before. For one thing, that engine should never get over 4800 rpm, let alone 5200.
One thing you might check on, is make sure the cable is free to swing back and forth (Fore and Aft) along with side to side in the shuttle valve. If it's binding, it could be causing a problem.
Does it only happen when turning ? Does it sound like the noise you hear when you are turned over against the lock?

 

[mark1905]

Re: Power steering screeching at high RPM's

Re: Power steering screeching at high RPM's

I think that my tach is wrong, by the way.. It's got a 19 pitch prop on there and says that it's redlining at 5100.. It also swings a little when you knock on it so I don't know how reliable it is.

Cable is free and not binding.. I do notice a little play in the area where the cable goes into.. it kind of bounces a little in and out with the steering wheel play.. not by much. I never looked at it before to notice whether or not its normal or not.

Only happens when turning, and it is definitely RPM related. If the engine is at lower rpms, it won't do it. It sounds like a rattle/screech/shimmy sound.

Last summer when I first heard it, I thought it was the pump low on fluid.. almost sounds like that noise.. yeah.. when you are turned over against the lock. It's not coming from the PS pump though, I pretty much have it isolated to the ram assembly on the transom.. The PS pump is brand new now, too.

 

[Don S]

Re: Power steering screeching at high RPM's

Re: Power steering screeching at high RPM's

Go up to the Adults only sticky and go the the Mercriser manual section and download manual #14. There is a section on power steering that may help track down the problem.

 

[mark1905]

Re: Power steering screeching at high RPM's

Re: Power steering screeching at high RPM's

We've been looking at it all day and can't seem to find anything that pertains..

 

[a70eliminator]

Re: Power steering screeching at high RPM's

Re: Power steering screeching at high RPM's

Seems like it's gotta be tied to hydrualic fluid flow, like it's screaming as it passed through a connection fitting there shouldn't be any teflon tape on flared fitting, one little stray piece can act like a reed and cause a screeching shrill.
Just a wild wild quess is all.

 

[Don S]

Re: Power steering screeching at high RPM's

Re: Power steering screeching at high RPM's

The original pump went bad, it's not hard to imagine pieces of the old pump getting into the cylinder and causing problems.

 

[JustJason]

Re: Power steering screeching at high RPM's

Re: Power steering screeching at high RPM's

are you sure your not hearing the pressure relief valve opening up?

 

[Don S]

Re: Power steering screeching at high RPM's

Re: Power steering screeching at high RPM's

are you sure your not hearing the pressure relief valve opening up?

It's in the pump, and he says the sound is from the cylinder.

 

[JustJason]

Re: Power steering screeching at high RPM's

Re: Power steering screeching at high RPM's

It's in the pump, and he says the sound is from the cylinder.

I hear ya, but what if the valve was opening up dropping pressure across the system. Think it would be possible to hear some kind of "shudder" from the ram?
PS.... i've never heard a ram screech either... it's just a shot in the dark. Obviously the poster would have to have a guage set to verify his pressures and see if there is a drop.

 

[mark1905]

Re: Power steering screeching at high RPM's

Re: Power steering screeching at high RPM's

It's in the pump, and he says the sound is from the cylinder.

Yeah it's for sure coming from the transom mounted actuator.

What is weird is how it started last summer only happening when I was at WOT and would turn.. it is dead quiet as long as the wheel is not being turned or holding through the turn.. just when the steering wheel is physically being turned.

Also, how it is progressively getting worse. Not louder, per se.. but happening at lower and lower RPM's, and how happening when I'm not turning but at WOT.

 

[Bondo]

Re: Power steering screeching at high RPM's

Re: Power steering screeching at high RPM's

What is weird is how it started

Ayuh,... Nothin' Weird about it,.. sorta normal progression for bad to Worse,...

I've never had any issues with an actuator before,...

I've taken them off, Installed 'em,+ know how they work,...
I can see where it might be stuttering between switching,+ pushing thru it's cycles,...
Seems it'd be quite a chore to Observe it doing it Too.... WOT, in a Turn,..??..

Finding a used 1 shouldn't be to hard on ebay,... There used to be piles of them going cheap..

 

[mark1905]

Re: Power steering screeching at high RPM's

Re: Power steering screeching at high RPM's

Seems it'd be quite a chore to Observe it doing it Too.... WOT, in a Turn,..??..

Auditory observation only..




Yeah, I think the next step is to pick one up on Ebay.. found a bunch of brand new ones for under $120

 

[mark1905]

Re: Power steering screeching at high RPM's

Re: Power steering screeching at high RPM's

So.. took the boat to the lake today to meet the mechanic.

We get it on the water.. I make it make the sound.. he looks at me and says.. "I have never, ever heard a sound like that..".

We couldn't figure out if it's coming from the steering ram or the transom/drive unit..

Not the gimbal bearing.. that was replaced. Ujoint looks fine when we took off the out drive to do the gimbal. Remember that my bellows were cracked which made the gimbal go bad. Could water have messed something else up back there?

Growling/rubbing noise from the rear of the engine in the coupler area while turning at high RPM's.


Mechanic literally could not figure it out, and told me to just drive it until something breaks. There has to be a better way..

Has anyone ever run into something like this?

 

[JustJason]

Re: Power steering screeching at high RPM's

Re: Power steering screeching at high RPM's

Here's the deal.... are you willing to pay for 5 hours of diagnosis time at 100 bucks an hour to find a 100$$ part that is bad.
either way.... find out what your engine is actually turning for rpms with a shop tach.

 

[chiefalen]

Re: Screeching from transom area at high RPM's while turning

If that were my boat i would get rid of the power steering, you don't need it.

What you should be doing is finding out why the tach is messing up.

That tach problem can cause you a different problem latter.

 

[mark1905]

Re: Screeching from transom area at high RPM's while turning

If that were my boat i would get rid of the power steering, you don't need it.

What you should be doing is finding out why the tach is messing up.

That tach problem can cause you a different problem latter.

Will do..

It's always drifted a little and you just give it a little thump on the glass and it goes back to "normal"..

It may not be far off.. it says that with a few people in the boat that WOT is about 4800. With a totally empty boat (plus driver of course) and trimmed all the way up, I've had it to 5100. Remember that as per the info stamped on the spark arrestor cover, redline is 4800.

It's an 18ft Dynasty BR (Same mfg as Polar).. running a 14 1/4 x 19p SS 3 blade prop.

 

[Don S]

Re: Screeching from transom area at high RPM's while turning

Take the PS belt off and go for a ride and see if the noise is still there. If it is, you at least know it's not the steering system causing it.

 

[mark1905]

Re: Screeching from transom area at high RPM's while turning

Take the PS belt off and go for a ride and see if the noise is still there. If it is, you at least know it's not the steering system causing it.

Brilliance!

 

[Bondo]

Re: Screeching from transom area at high RPM's while turning

Quote:
Originally Posted by Don S
Take the PS belt off and go for a ride and see if the noise is still there. If it is, you at least know it's not the steering system causing it.
___________________________________________________________________

Brilliance!

Ayuh,...

Don's been accused of That before,.................