OE Hydraulic Steering No Assist
 

Circa 1996 OEM cable actuated hydraulic rack via helm and hydraulic PS Pump on 7.4 LX MPI twins in front of B1's.

From one outing to the next the steering felt as if it had no power assist. I spoke to my mechanic about it and after sending him a video of the fluid in the PS reservoir he noted there wasn't enough "disturbance" and the pump was bad. I replaced and bled the pump as per the repair manual, the reservoir required about and inch of top off which to me signals the pump is moving fluid. Today on the water the steering doesn't feel any better. It's generally hard to steer in either direction the past two outings but the below is what really grabbed my attention and alarm for concern.

While on plane the assist feels great turning left, but when turning right (to straighten from) a left hand turn I have to grab the wheel with two hands and yank it back to middle. When turning right and then steering left (to straighten out) there is "normal" assist feel. The manual reads "hard steering to starboard- cable too long or restricted", "hard steering to port-cable too short or restricted."

Is it a matter of the internal cable workings simply binding between outings due to age or should I be looking to the rack and or helm as well?

Thanks for any help you can lend!

Keith

Marine/boat power assist steering is not the same as auto power steering, It will only assist when a load is applied to the actuator normally when on plain. If it's stiff when docking/going slow it would tend to be the cable or helm. Disconnect the pin from the actuator to the drive arm linkage and see if the drive moves free.

The cable moves a shuttle valve in the rack (control valve). The valve doesn't move much, but this movement causes the hydraulic pressure into one side or the other of the piston. If the cable is loose or the slots are not vertical (item d in top right pic) then flow is restricted

https://cimg1.ibsrv.net/gimg/www.off...3724c049b8.jpg

While not on plain the steering feels tight (compared to all outings before last 2) when going slow and docking but not nearly as bad as I mentioned above about being on plain and turning right.

So disconnect the pin between the rack and drives to take the drives out of the equation? Fire the engine and work the steering while on the trailer to see if it feels more free? If it feels the same I'm looking at rack, cable or helm?

Keith

Thanks I'll check the cable for being tight and properly aligned. For what its worth I did nothing with nor near the cable to change its orientation since the issue started.

Keith

The cable was tight; however, the (D) Cable Guide Tube slots were positioned at 1 o'clock (toward the transom) in relation to the rack. I loosened the steering cable nut and oriented the Cable Guide Tube to 12 o'clock. I guess it's time for a test drive.

I did notice the Cable Guide Tube moves about 3/4" within the rack when changing direction from left to right and right to left steering at the helm. Is this motion normal?

Thanks for your insight
Keith

if you can get to it, disconnect the cable from valve at transom, see how it turns not running, should be smooth both ways. If sticky and binds replace the cable, if not the valve is bad(which I'm betting form how you described

PM sent

I converted my steering to full hydraulic, so I have a perfectly good shuttle valve sitting on my workbench. If you're interested make me an offer, it's not doing me any good.

1. Did the above and the steering wheel moves without issue (both directions) so we can rule out the cable and helm.

2. Started the boat yesterday (on trailer, steering system fully connected) with the cable guide tube slots vertical and the steering is still overly stiff to starboard.

I still haven't removed the pin to the tiller arm to rule out drives binding but as stated above, with the engine off the steering wheel moves equally and freely in both directions. The issue only seems to present itself when the power steering system is in operation while the engine is running and again only when steering to starboard.

At this point and as most mention above, the issue most likely lies in the Control Valve Assembly on the rack.

Keith