AutoPilot Pump not steering to port (but can hear it trying)

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Hi all,
I tried my autopilot for the first time this weekend and it failed. I spent time with the Raymarine tech on the phone today. After some extensive debug, we ended up putting 12volts directly to the pump and my outboard moves starboard but not port.
As always help is appreciated
Thank you
Steve

A couple of questions:

1. I want to remove the M81120 type 1 hydraulic pump, how do I keep the hydraulic fluid from draining? Is there any tricks?
2. Has anyone every seen this issue? Is there a way to get the pump un seized?
3. Is there a schematic / diagram of the pump workings?
4. Any other ideas welcome

 

[Ekea]

is the autopilot new, or just new to you?

 

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is the autopilot new, or just new to you?

The boat is new to me this spring and illness kept me from getting out much. the auto pilot came with the boat (2008 GW)

 

[wspitler]

If the pump produces pressure for starboard steer, it is not seized. It either reverses polarity to pump in the opposite direction or there is a electrically controlled valve that ports fluid in the desired direction as directed by the course computer. Your course computer tells it which way to pump, port or starboard. It could be a problem with the course computer or the electro valve in the pump if it has one. I'd do a good check on the wiring from the course computer to the pump before deciding it is a bad pump. I'd also check the electronic rudder limits that can be set in the course computer (see the manual). If the pump runs when trying to steer to port, then it could be an internal failure of the steering ram itself. There are also check valves in the system to prevent pressurizing the helm pump. I'd recommend more diagnosis before replacing the pump. I'll attach the manual.

 

[Pop]

If the pump produces pressure for starboard steer, it is not seized. It either reverses polarity to pump in the opposite direction or there is a electrically controlled valve that ports fluid in the desired direction as directed by the course computer. Your course computer tells it which way to pump, port or starboard. It could be a problem with the course computer or the electro valve in the pump if it has one. I'd do a good check on the wiring from the course computer to the pump before deciding it is a bad pump. I'd also check the electronic rudder limits that can be set in the course computer (see the manual). If the pump runs when trying to steer to port, then it could be an internal failure of the steering ram itself. There are also check valves in the system to prevent pressurizing the helm pump. I'd recommend more diagnosis before replacing the pump. I'll attach the manual.

Thank you for the reply. I am going to do more diagnostics for sure. do you have any idea how the hydraulics work inside the M81120 type 1 hydraulic pump? that my help me a lot. It looks to be electric over Hydraulic but not sure what the motor is turning inside the hydraulic portion.

 

[wspitler]

Check out the manual that I attached. It appears to me that is a simple motor that runs either clockwise or counterclockwise most have some sort of pistons or impellers that pump the fluid and direction depending on the rotation direction. If the motor is running and not just humming when it tries to steer to port then it could be airlocked you could try bleeding at the motor or at the helm. Also a bad check valve could allow fluid to go in the wrong direction and not allow a port turn.

 

[Pop]

Check out the manual that I attached. It appears to me that is a simple motor that runs either clockwise or counterclockwise most have some sort of pistons or impellers that pump the fluid and direction depending on the rotation direction. If the motor is running and not just humming when it tries to steer to port then it could be airlocked you could try bleeding at the motor or at the helm. Also a bad check valve could allow fluid to go in the wrong direction and not allow a port turn.

Thank you, I agree it just a simple motor that changes polarity to change direction. I will try and find if there is a check valve in the system and also trying bleeding it out.

 

[Pop]

If the pump produces pressure for starboard steer, it is not seized. It either reverses polarity to pump in the opposite direction or there is a electrically controlled valve that ports fluid in the desired direction as directed by the course computer. Your course computer tells it which way to pump, port or starboard. It could be a problem with the course computer or the electro valve in the pump if it has one. I'd do a good check on the wiring from the course computer to the pump before deciding it is a bad pump. I'd also check the electronic rudder limits that can be set in the course computer (see the manual). If the pump runs when trying to steer to port, then it could be an internal failure of the steering ram itself. There are also check valves in the system to prevent pressurizing the helm pump. I'd recommend more diagnosis before replacing the pump. I'll attach the manual.

Thank you for the manual. it does reverse the polarity. I put power directly to the motor and switched the polarity manually. still no turn to port just starboard worked (although the pump made the same noise in both directions)

 

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Thought I would provide an update to my auto pilot issue: I got in touch with the pump company from England. They were a fantastic help! talked me through what was likely wrong and how to fix it. He also provided me a schematic of the pump plumbing which was also a fantastic help. I disassembled the pump per his instructions, cleaned and buffed the parts that are suppose to move (a piston like slider and check ball). REINSTALLED THE PUMP AND IT WORKS GREAT! I love having auto pilot while trolling !!!

 

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Thought I would provide an update to my auto pilot issue: I got in touch with the pump company from England. They were a fantastic help! talked me through what was likely wrong and how to fix it. He also provided me a schematic of the pump plumbing which was also a fantastic help. I disassembled the pump per his instructions, cleaned and buffed the parts that are suppose to move (a piston like slider and check ball). REINSTALLED THE PUMP AND IT WORKS GREAT! I love having auto pilot while trolling !!!

Additionally it cost me nothing to fix. I also have the schematic of the pump if anyone needs or wants it

 

[glacierbaze]

Go ahead and post the schematics, it may help someone doing a search in the future.

 

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Attached are the schematics for the type one auto pilot pump. Page 3 shows the pump mechanism