Power steering quits working at high trim?
 

Does anyone know why my power steering would lock out with elevated trim. I blew up one powersteering pump already. I'm not even being allowed to trim up half way before the steering get extremely hard. I'm wondering if maybe my gimble bearing is causing this since it has recently started to make noise.
Any ideas would be great.
Thanks
Put Away Wet

Ayuh,... My guess is, yer trimmin' too high, causin' the linkages to bind at the tiller arm,.....

You'll have to Look,....

tiller arm does not change angle no matter what the trim angle

Subscribed.

I work on one that does the same...but does not blow anything. Locks up right at top rpm (5300-5400) and trimmed pretty high (for best speed.) But, on this one, if throttle is pulled back, and trim the same, the power steering comes back. Figured a belt, but it isn't.

Always wondered if maybe pump spinning too fast ? Or needs remote reservoir as it doesn't have one. Dunno. Will keep ears/eye's open to this thread.

Perhaps too much resistance from the drives at speed while trying to turn setting off the bypass valve in the pump?

Just how far are you trying to trim this boat?
There is a measurement of length on the trim cylinders that you are not supposed to go beyond; but I can't remember what it is on a typical Bravo setup.
I'll ping BUP to look at this thread. He'll know.

Is this a new phenomenon, or something you have been living with?
Full hydraulic? Pics and more details would help.

Mercruiser spec is trim ram center bolt to center bolt is 21.75 inches for trim limit / trim for running in the FULL UP position. You do this measurement in full trim only position NOT TRAILER UP TRIM position. it is done out of the water with a measuring tape.

With that said the power steering should not stop working if you past this 21.75 inch measurement.

Also I take it we are talking about Mercruiser and a Bravo app here ?.is this correct ? What year ? I take it a 2007 Nordic heat boat and with Mercruiser & Bravo ?

what is your steering set up ? OEM stock or is the steering actuator gone and full hydraulic or even hydraulic with the actuator (internal only ) please explain your steering set up and the steering pump U are using. Is this an Auto steering pump replacement and do U have the correct pressure relief valve installed your steering pump reservoir ?

Are there any check valves in the system that can be stuck or faulty? Another guess would be the oil is cavitating or frothing leaving the pump with nothing but air.

That's my guess.

The trim angle extends the steering rams, needing more fluid, and the pump can't supply it.

really need to know the whole steering set up because at this point and time its a dart throwing contest .plus the outdrive set up - do you have an extension box ?

Also the other side of the coin for resistance is the higher you trim up the outdrive the further out of the water the drive / bullet comes up out of the water so hence less resistance against the steering components.

Do you have a power steering cooler and if so is it big enough in size for proper cooling ? If no pwr steering cooler you need one and the correct size for your set up.

The boat is a stock 425hp HO (other than the headers) with a bravo 1, no added on hydraulics. The problem started last summer with a Mercury factory pump. I'm not trimming any where near as high as I have the last 7 years with this boat. After the pump change last year it had the same problem. I don't have any fluid leaks and all fluid levels look good. When I'm running about 4800rpm and I'm trimming up the steering gets extremely tough to turn when I bump the trim up just below half on my gauge. When I bump it back down, the power steering works like it should (I don't think it's a RPM issue).
I don't know I'm at a loss. This weekend I'm going to look close for something that interferes with pump lines when trimmed. Other than that looks like I may have to bite the bullet and take it to my dealer.
Thanks for all the responses.

HIgher trim, higher steering load, maybe it is maxed out on assist pressure. Probably turns easy in one direction, but not the other?

Have you put a gauge on any of the hoses? One on the pump's discharge may show a pressure spike.

Is this a single or double ram set up? Cable or hydraulic helm? The devil is in the details.

Like above asked is this a cable steering set up and stock actuator - (connected to inner transom assembly) set up ? if cable steering is this rack / pinion or rotary steering system ?

You mentioned changing out the steering pump / reservoir once before - did you clean out and flush all your power steering lines, power steering cooler and the actuator, You could have a restriction in the system

On your steering pump / reservoir is the correct relief / pressure valve installed ? Did you buy an auto unit ?

I'm interested in this one. He mentioned in post 12 that it is a stock Merc system with no add on or full hyd steering. He also mentioned that he changed the pump. My guess is that it's an automotive pump with the incorrect pressure relief valve.

?? Find anything

This problem started with the last power steering pump which was a Mercury pump. When I trim up it becomes extremely hard to steer (not pulling any one direction; just hard to turn). Then one time last year I was trimming up and it blew the front seal out of the pump. I did replace the pump with an automotive replacement ($40 vs $475 sounded like a good option). When I put in the auto pump the same problem is happening. I haven't blown the pump yet, but I'm not really running the boat up on much trim. I replaced the pressure release spring on the new pump with my Mercury one.
I guess I need to take take a closer look and see if anything is binding the fluid lines or the steering when trimmed up. I have good fluid level and no leaks.
My original concern is that the gimble has started to make noise and I was courious if it could be binding something at high trim causing the hard steering
I'm going out boating again today, I will look for something binding within the engine compartment.

Did you ever find any thing? Have you tried running on a hose trimmed up with some one steering side to side, or disconnecting it from power steering to see if drive or gimbal is the problem?

Could also be his steering actuator going bad. Mercruser has pressure gauge testing and diagnostic procedures to follow along to pin point the problem. OEM Service manuals is your friend. They are a must if you want to work on your own apps.

Op
You asked for help, and a lot of people would like to.know the solution, please keep us in the loop!

^^^^Yup !!!!^^^^

Again, I got one doing it and I would love for someone else to figure it out. LOL.

I had this exact problem years ago and it was a piece of rubber chard looking material caught in the pump pressure relief valve. Only did it at wot and would pull hard right. It would go back to normal once slowed down again. This valve is the fitting that the hp line screws into on the back of the pump and is easy to inspect and clean out/
.

Well, I put 6 hours on the boat last week and the problem continues. I would trim up at idle and I had no problems. At about 4600rpm and just over half trim the problem is reoccurring. I did notice I have about 1/8 a turn of no response (slop) in my steering wheel. It looks to me I need to take it in to be looked at. I think this is past my comfort level.
Thanks for all the advice.
I think the "trade in light" is starting to flicker too.