Power Assist: 2003 4.3 V6 190hp, Alpha 1 Gen 2+

[BAron Sportsman]

Power assist locks up steering solid if rotated to full lock positions left or right. The assist is one of the newer types and I believe still the current units.
With the engine shut down, the spring actuator appears delayed returning when coming off full lock positions and I assume this is effectively now trying to send fluid in both directions at the same time creating the lockup.

Forcing it a little too much blew out one of the "O" rings. Removed it, stripped it down, no damage inside that can be seen, spring appears good. New "O" rings all round rebuild and replace. The wrench slots are set in the vertical position as they were before. The big nut at the other end had been locked into place exactly half a turn off full screwed in and was set back in that position, in fact we tried several positions for it from 1 and half turns further backed off to full tight. When the engine is running it still delay's the return of the spring actuator and locks the fluid once more.

For the moment I have removed the pump, lines and all seals in the actuator and piston so it can't build pressure and just use it as a complete manual application. Even like this it's still notable to catch on initial return from both full locks from the delaying actuator, however it pops back over it off course with the fluid pressure no longer in play. Problem here is the steering is very heavy, pulls left and gets heavier and worse with speed. For manual steering I would expect this as the manual steering on the Volvo that was in it before the Mercruiser did the same thing only not as bad but then the V6 certainly does pump out a crackajack more grunt than the little 2lt Volvo did. Torque reaction is having a lovely play.

Mercury dealers are telling me that this isn't a common problem for these power assist setups. Can anybody shed some light on that and advise me of different. I'm told they are not repairable and throw away? I swear Don will be my man here. You helped me heaps when I was running the Volvo.

Thankfully I discovered the problem backing away from the dock on the first launch and didn't discover it at higher speed. Locked up steering on full lock could be very dangerous.

Notes: The engine is second hand but young hours and everything else operates fine. Second launch with the modified steering proved that. It goes quite well actually. Kinda surprised me!

Helm end of the steering is fine, cable is new and operates softly and freely if the cable is disconnected from the assist actuator. Can turn lock to lock with one finger with no catching.

The only other thing that is different to how I bought it is we rebuilt the gimbal before fitting. Thought it was a sensible idea while it was already out of a boat.

Any clues on this assist Actuator? Repair or ditch and buy a new one?

Cheers all

 

[Fun Times]

Hi there, unfortunately Don is no longer with us down here due to there seemed to be a problem with a bigger boat upstairs and Don was called upon to go help repair it. I just hope the owner of the big white boat in the sky had his serial number handy.

The reason the boat is steering hard and wanting to go left is due to once you removed the no feedback power steering system, you would have needed to add a Mercruiser anode steering fin to help offset the steering torque from the propeller. You should have a flat plate just above the prop since you had power steering. Adding a fin and carefully adjusting it while out on the water will help with your new steering issue until you repair the original power steering system then you'd need to go back to a flat plate. Here's the fin anode you'd need, http://www.iboats.com/Boat-Parts-Ac...4--searched.1--session_id.184045050?q=31640Q4

Depending on the model yours is and how easy it looks to come apart, some have attempted to repair their actuator in the past by sourcing new parts at hydraulic type repair shops, eBay, etc. some have done it successfully (< mostly Volvo) but most have not as the actuators weren't designed to be repaired/come apart and there are no repair kits available from the manufacturer. Your design being an 2003 from Merc, I don't "believe" you'll be able to.

I faintly recall seeing a few actuators lock like you are describing, one seemed to be hitting the boats transom as it wasn't cut out probably and the other one we replaced the actuator to solve the problem.

Be sure to try disconnecting the actuator from the steering lever and turn the drive by hand both inside and outside of the boat before deciding if you really need a new actuator.

Keep us updated, good luck.

 

[BAron Sportsman]

Thanks for that mate. Firstly, sorry to learn about Don. There's a good man lost, never mind the endless help he's supplied to hundreds of boaties over the years, including myself.

I half expected I'd now need one of those fins to offset torque and looking into it. My old Volvo 280 drive had one of those and I can see I'm definitely needing to fit one in between times. It's quite an eye opener to experience torque reaction at full strength without a compensation or offset. At higher speeds it was taking me all my time to keep the boat in a straight line.

I'm actually hoping the fin will work as good as it did on the Volvo because at the end of the day I actually have no problem with full mechanical steering. It's all I've known in every boat I've owned or used (Except one only), in 30 years. From what I'm understanding, these power assist type set ups are certainly not true power steering as it's still cable to the actuator. Instead it's more designed to simply overcome this torque issue and keep the boat in a straight line. So it's either the assist version or the without it, it's the fin version.

If this overcomes the problem good enough, I'll be honest with you, I probably won't even bother to ever return it to powered. To me, every accessory added is just another expensive part that can go wrong and spoil your day. I'll still be as happy as always with mechanical one I bleed some of that reaction back out of it.

Thanks once again for your help.
And once again, sorry to hear about Don.

Stay tuned on this one for the result and another I will post shortly to learn a little more about Optimum RPM's.

Cheers.