Mercruiser Power Steering Woes - Lots of reads, pics, and a video!

[newbienewb]

Hi Guys,

Ive done a bit of a search and even though there is a fair bit of info on power steering, im having a bit of trouble working out whats wrong with mine.

It feels as if there is just simply no power steering at all. If i turn the wheel as fast as i can, i almost get the sensation that it actually improves (or works a little bit), but then just goes back to not operating at all. THe steering is heavy, but doesnt feel like its catching on anything. The steering feels precisely the same wether the engine is running or not.

I hear no evidence of the pump loading up as i turn from lock to lock.

The boat is currently on a trailer in my driveway.

First off, the boat is a 2001 Whittley Cruisemaster. It is running a 350 MPI Magnum Mercruiser, with a Bravo 3.

I'm fairly handy mechanically, so im trying to diagnose / fix this myself.

As far as i see it, there are a few critical components to the power steering:

1) A freely moving helm steering mechanism.
2) A freely moving and non binding steering cable from the helm down to the actuator.
3) A freely moving outdrive leg.
4) A freely flowing fluid system (including the power steering fluid cooler)
5) A good condition and appropriately tensioned serpentine (or V) belt driving the pump.
6) A well maintained and operational power steering pump.
7) A working and operational power steering actuator.

So, these are the points I am focusing on as i try to diagnose my power steering issue. This is what i have done so far.

1) I have disconnected the steering cable at the helm end, and have confirmed that the steering wheel turn completely freely. A flick with one finger will spin it no problems. I have assumed this is not the cause.

2) I reconnected the steering cable at the helm, and disconnected it at the actuator end. The steering wheel still moved freely, and I am easily able to turn it with one finger. I have assumed this is not the issue.

3) I have disconnected the actuator from the outdrive leg, and then manually moved the leg left to right outside the boat. The leg moves extremely freely with no binding or grinding at all. The action is very smooth and takes little effort. I have assumed this is not the issue.

4) I have removed all power steering hoses, and have removed the steering fluid cooler. I can easily blow both air and fluid through all components with no issues. No big lumps or blobs came out of any of these components. I have assume there is no blockage or restriction in the flow.

5) My belt is in good condition, and is nice and tight. Not really to much to this one. But i have confirmed the belt is snug. No other components are slipping. Raw water pump pumps well. and the alternator is charging without issues with no fluctuations in voltage.

6) The pump is the thing i suspected from the get go, so i borrowed a pump off a mate of mine and have installed that. It made no difference whatsoever. He assures me it was working fine when he got it. It has been sitting in his garage for the better part of about 12 months, with fluid in it. Given everything I have tested above, im wondering if this pump is faulty as well.

7) I have removed the actuator, and have played around with it a bit trying to understand the action. If i attempt to pull the steering rod up and down while the control valve is in the neutral position, it has resistance. Obviously it moves a little, but returns to its original location when i get go. If i move the control valve in either direction, I can move the steering arm freely. Here is a video of me operating the actuator manually.



I dont know alot about these, but following the flow diagrams in the mercruiser manual i have (images of pages attached), it appears as though the action i am seeing when i operated it, is consistent with the diagrams.







So, thats where i am at. These are my questions.

1) By me operating the actuator manually as shown, am i really proving anything?. I know im proving that when the control valve moves in either direction, it allows me to move the steering rod freely. Is this enough to suggest that the actuator is working correctly?. Is there any way i can test it further?. I was thinking of trying it with compressed air.

2) Have i proven adequately that the steering cable is working properly?. I did not have anyone holding or loading the cable when it was disconnected. The thing that makes me think the cable is OK is the clinical evidence that when i run the enigne and turn the wheel quickly form left to right, i do feel "spurts" of the steering working. I would have thought if the cable was binding, it would not momentarily "free up" like this.

3) Even though ive put a different pump in, and even though that pump was allegedly working fine. What do people think about the likelihood of me having another faulty pump. I know as well as the next bloke it "could" be faulty, but based on everything else in this thread........what do people think?
Does anyone else have any other suggestions as to what or how i might test further?

Many thanks,

Dave

[Greg P]

Dave

just my $0.02 worth. It looks like a very basic hydraulic circuit, I think you are on the right train of thought. The cable is free, all that would need to be check later is that it is adjusted for correct travel for the control valve movement both ways. Check your pressure relief valve for wear on the seat of the poppet or broken spring, if pump is supposedly alright (don't write it off as the issue though) and you are sure that the system has been bled of air then can only be piston seals in the cylinder bypassing if the control valve spool/housing + associated seals looked okay.

Not sure what the hyd fittings are and if they have test fitting plugs to put a hydraulic gauge in but if they do then easy enough to check relief valve setting of pump.

my guess, if you are sure it has been bled of air in the cylinder, it will be either the pump/relief valve or the piston seals in the ram.

[newbienewb]

Hi Greg.

Thanks for taking the time to reply.

Did you get a chance to watch the video at all?. It shows me operating the actuator out of the boat. If I don't move the control valve, the steering ram certainly shows resistance, which leads me to think the seals on the piston are ok???.

Hooking up a pressure valve would be ideal. I don't have one though I'd have to buy something to put inline as there are no test fittings like on a fuel rail.

Dave




Sent from my iPhone using Tapatalk

[The Woo]

Dave I'm thinking a faulty or stuck pressure relief valve mate at the pump mate. You've isolated pretty much everything else, and your ram video appears situation normal to me.