Mercruiser 3.0 Intermittant Power Steering

[ashleygoodin]

Okay, I am relatively new here and by no means a mechanical genius but I do know how to work my way through troubleshooting and heavy maintenance.

I have an '88 Chaparral 178XL with the 3.0 Mercruiser I/O. When I bought the boat and was prepping for putting in for the first time, I noticed that the power steering fluid was low, so I topped it off. We put in and the power steering wasn't working. Belt and tension were good (belt was a bit old, but OK and not very cracked or rotten). I noticed that at full steer left/right, the pump would nearly stall and spin the belt. I know that that is not an uncommon occurance. Ran the boat for about ten minutes (before I noticed that I had missed the fuel filter at the carb when it plugged up and allowed me to idle back to the ramp). The power steering started working about 5 minutes in and performed very well. I attributed this to the boat sitting for a year before I bought it and if it was low enough on fluid, it may have had to work the air out of the system.

We have taken the boat out multiple times in the past month. Checked all of the fluid levels pre-trip and everything is staying topped up, including the power steering fluid. No problems with the power steering.

Put in last weekend - no power steering. We were running the boat at WOT to get some numbers for a new prop for part of the run and then trying to teach some friends to ski for part of the 6 hours we were out. No power steering for most of the trip, but then at moments when I was circling to bring the rope around, I could feel the power steering kick in and then stop, kind of like it was working out air bubbles.

I had a bit of a rough pulley on the alternator and lost the v-belt there on the last run, so I am going to sand it and put some hi-temp paint on with a new belt this afternoon, but I am wondering about the power steering. I am going to replace the belt there too, but should I just go ahead and change the pump too?

I suspect that the pump could be bad / cavitating thus causing the intermittant steering and can replace that, but should I look for some sort of blockage elsewhere?

Please give me your advice. I have about two good weekends left before the water temp drops and I want to take advantage of them...and will even if it means that I have to use power steering by Armstrong & Speed.

 

[indy440]

Re: Mercruiser 3.0 Intermittant Power Steering

i would start with a new belt, then make sure your fluid is topped off. Start the boat out of the water on muffs and turn the wheel lock-to-lock several times to make sure you actually have all the air out of the system...

 

[Bondo]

Re: Mercruiser 3.0 Intermittant Power Steering

Ayuh,... That's sound advice from Indy,...
A couple more Points to look at,...
Check to make sure the sterring cable is Free,+ Lubed where it passes thru the aluminum tube mounted on the transom...
Also check to be sure the P/S rack/ valving is free,...It senses cable pressure to assist,+ the valve must be free to feel the cable...
1 last point,...
Pull the return line from the pump, point it into a waste receptacle,...
Have Somebodyelse turn the wheel lock to lock, at idle, slowly,...
While you pour fresh ATF into the Reservoir,+ watch the return fluid for Water....
When you see Fresh Clean fluid,... Button it back up....

 

[ashleygoodin]

Re: Mercruiser 3.0 Intermittant Power Steering

Thanks for the help. I put on new belt this afternoon and feel like a dumb***** for asking the question now. I think that I know the answer after actually installing the new alternator belt.

The alternator belt that failed near the end of the run was probably close to the end of it's life (and the end of the tensioner) when we put in last weekend. The alternator belt runs from the crankshaft pully to the idler (what would be the water pump pulley in an auto) and then around the alternator, where it is tensioned. The power steering pump runs from the idler to the ps pump. As the alternator belt slipped and disentigrated, probably partially as a result of some demand on the ps pump, the idler would slow down or speed up (then eventually stop when the alternator belt broke), causing the intermittant problem. No alternator belt = no drive for the power steering pump.

When I take the battery off of the charger tomorrow and pop it back in, I will put the muffs on and then go from there. I think that the new belts probably solved the issue.