play in power steering

[seano]

I am wondering about the way my power steering operates---perhaps someone has been here before...

Turns at cruise(3500 rpm) are very nice, the boat leans nice and carves pretty well, but there is something that has bothered me a little bit---there appears to be some slop in the wheel--I replaced the helm and cable(Kiekaefer tilt helm)---everthing is brand new...the only thing that is not new on the boat is the fuel tanks and the hull---I replaced every thing with new; so I dont understand why I have play in the wheel. While running at speed, if i turn the wheel a little the boat doesnt respond, i turn it a littel more and it still doesnt respond, if i turn it a little more, it responds to the extreme! There is plenty of power steering fluid and with the boat at the dock(not running), I can see play at the power steering ram where the cable threads on. Is this normal? Any thoughts?

[PaulO]

Seano,
It's hard to say how much play is normal. Every mechanical system has some play and the steering is no exception. Every time there is a transition such as from the radial motion of the steering wheel to the linear motion of the control cable, there is some play. When you add up all these transitions and the amount of play in each, you can have an amount of play that seems large. Usually, some amount of play is not bad. What you may have is a problem with the adjustment of the tab that mounts on the underside of the anti-ventilation plate. If you drove the boat without power steering, you might find that at slow speed, the steering pulls to one side while at high speed, it shifts and pulls to the other. This would be because the tab cannot correctly compensate for steering torque throughout the entire operating range by staying in one setting. Your problem may be that at the point that the steering changes to pull from one side to the other takes up the slack in the steering and becomes an "oversteer". My suggestion is to adjust that tab considerably to one side and see if it alleviates the "oversteer". If so, from there you can gradually adjust nearer center to get the right setting.
PaulO

[Forrest]

Though usually reliable, power steering problems can be a bear to troubleshoot and correct. Some play that you see back where the steering cable housing attaches to the mounting tube is normal since the mounting tube must move somewhat to actuate the power steering control valve; however, excessive play is not normal. When you turn the wheel a little to the left for instance, reactive pressure from the cable housing is momentarily place against the mounting tube to the right which in turn moves the power steering control valve momentarily. When the control valve moves, the pressure from the pump causes the power steering ram to move in this case to the left. When the valve return to the center position the ram stops moving. Move the valve a little and the ram moves slowly, move it hard over to its stop and the ram moves quickly. Keep you fingers and hands out of movement of the ram!!!

Why do you have the situation that you describe? Quite possibly, there is excessive wear in the mechanical joint where the actuator lever connects to the control valve. To check for wear in the actuator lever, remove the cable end and cable housing from the mounting tube. You will find a rather large special-nut that attaches the mounting tube assembly to the control valve assembly. Remove that nut and the cable mounting tube. The threaded "nub" that you see once all this stuff is out of the way is the actuator lever. Now, start the engine and carefully move the actuator lever from one side to the other noting how much slop or movement is necessary before the ram starts to move. If the movement is excessive, parts need to be replaced to remove excessive play in the helm.

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Forrest

[seano]

paul,

The play that i can see is where the cable threads on to the power steering ram. if you move the wheel at the helm from side to side, you can watch the the cable mechanism move inside the power steering ram. This doesn't seem normal, and I have not tried this with the engine running...I will look at it tomorrow. BTW, I am not running any steering tabs on the anti-ventilation plate at all...there is just a flat zinc there. Should I install a a pair of these? (boat is a twin engine 28' Cigarette)

[Forrest]

Don't bother with installing and adjusting zinc tabs with twin counter-rotating props. The two props balance each other therefor steering torque is nil. The flat zincs are just what you want.

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Forrest

[This message has been edited by Forrest (edited 08-03-2000).]

[seano]

Paulo, Forrest,

Thanks for the information...I'll take a look this weekend...

Sean

[GeneD]

Hey!
Here is something I can sink my teeth into. I am somewhat of an expert on the Power Assisted Power Steering found on all Mercruisers with that option.
Forrest made a pretty good explaination of the mechanism and how to trouble shoot it. The only thing I would have added would be to check your gimbals out for wear. Grab the outdrive and see if the steering arm is worn by moving the drive from side to side. If this is worn out, you will notice right away.
If it turns out that the Power Steering Control Valve is blown out, here is a little tip that everyone should know. I have no idea what Mercruiser charges for that part, but I have owned a Corvette (Don have mercy) since I was 26 and have a bit of experience with these things. The Corvette and the Mercruiser use the SAME valve. The use a similar ram, only the Corvette one has a tie rod welded onto the end making it unuseable for the Merc.
Sooo, if the valve is shot, go and get yourself a rebuilt one, or a new one, from one of your local discount auto parts joints. They offer lifetime warrantees and it is the same exact part. Use my car as your own. 1975.
And hey, from the description you gave, it DOES sound like the valve.

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GeneD
007
Melbourne, Florida

[This message has been edited by GeneD (edited 08-04-2000).]