During docking the alarm for pressure oil sensor always indicate alarm after docking it stops
What could be the problem?
Which system? Main engine, generator, reduction gear, CPP, steering, tugger?
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Main engine
In any troubleshooting, the more info the better if you want the best answer, and the more questions you consider the more likely you’ll find the answer.
How about the rest of @Sand_Pebble’s question…reduction gear or CPP (or direct coupled/reversible even). For reduction gear, are you running at lower engine RPM when docking? For CPP, do you have different modes with the mode for maneuvering running a different RPM? Do you have engine driven LO pumps or separate motor driven pumps, or both. Do you experience different vibrations at maneuvering speeds? Where is the sensor located? Is there a gauge next to it or near by that you have verified the pressure is actually low? Have you pulled the sensor and calibrated it? Do you experience any power fluctuations during maneuvering? Any other alarms occurring consistently around the same time? Any other changes to the plant during only maneuvering vs sea speed? When’s the last time you cleaned the LO filter? What engine model is this anyway?
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Am operation hydro master engine hp/rpm 150/2100, engine number U966900Y PROPELLER DIA 1016
The sensor is connected directly to the engine and during docking I dock on low speed but on low speed the alarm is created on low speed
There is no guage connected near the sensor
And no other alarm is there during docking .
Have not worked on the sensor yet I have not calibrated the sensor
Is hard for some time during docking but not on idling and high acceleration
Your two choices are something is wrong with the sensor or the oil pressure actually is too low. You will need to plumb a gauge in there and have someone watch it. You also can take the sensor off and use an air compressor and gauge to rig up a way to see the exact pressure it trips at.
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I don’t know if I’m looking at the correct picture online but that looks like an interesting piece of equipment. Disclaimer: I’ve never worked with a Hydromaster unit. Is the diesel engine connected to it a Perkins which I found was common online? As @yacht_sailor said, you will need to verify what oil pressure you are actually getting & if it is low or not. Hopefully your engine has a lube oil pressure gauge to monitor, to see if the alarm is sounding at the correct pressure or not. If your mechanically inclined & have a parts store nearby this is easy to test if you don’t have a gauge.
If I didn’t have a pressure gauge on my engine, I would do the steps below, being very careful to always use the correct threads & torque on everything I touched.
- Look in the manual to see what is the low pressure alarm set point.
- If I had a Cummings or Perkins diesel engine, the lube oil sensor should be on the side of the block.
- Remove the sensor & take it to a parts store & ask for a sensor adaptor (ALL THE SAME SIZED THREAD!) A sensor adaptor is a “T” type fitting, picture below.
- I would also buy a pressure gauge in the lube oil pressure range of the engine. (BE SURE THE GAUGE THREAD IS THE SAME AS THE ADAPTOR!).
- I would install the adaptor in the place of the lube oil sensor. Then connect the sensor & gauge to the adaptor.
- Run the engine/thruster to see if sensor is alarming at correct set point or not.
Also Note,
- If the unit is new’ish & under warranty. I’d call the company that sold it & tell them to fix it.
- If low lube oil pressure is decided by a computer on a graduated scale then you might have a setting/computer problem which would explain why you get the alarm while berthing at lower hp/rpm.
- Check your dipstick to see if your sump is rising or making oil. If you have fuel dilution, at first, you might only get a low lube oil pressure alarm at low rpm’s.
- If you have 2 of the same Hydomaster units & no spare sensor, switch the sensor between the 2 to see if the problem moves with the sensor or stays with the same piece of equipment.
Good luck.
My engine type is 2600series Perkins desiel marine engine with150hp
The pressure gauge tends to decrease below 2bars at low speed and increase to 4bars at higher speed
Explain that also
From what I found online, below 2 bar is most likely low lube oil pressure for a Perkins 2600. When is the last time the oil was changed? Did you check for fuel dilution?
Because of that i changed the oil on Sunday 27/07/2025 and checked the oil levels are okay and no leakages for oil available
The oil pump is engine driven and lower RPM equates to a lower number of rotations of the pump. It’s a positive displacement pump. More rotations per minute means it’s pumping more oil and the pressure goes up.
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Low oil pressure on small engines is typically an error in monitoring. Bad gauge or faulty indication. Wiring if there’s a pressure transducer. Or it could be as simple as a bad gauge but you also have the alarm. That means you would have to have a bad pressure sensor for the alarm signal and a bad gauge. Unlikely. So that means you actually have low oil pressure. Like my favorite person Sand Pebbles said, fuel dilution. If you changed the oil, that should correct this. I don’t know the Perkins and I have limited data to look it up. Is the pump external? If so look on the pump and see if there is an internal relief valve. It will have a cap and under the cap a jam nut and a threaded piece with Allen head. Start the engine, loosen the jam nut and turn the hex clockwise to raise the oil pressure. Lock it down and watch the pressure when you raise the rpm. Not external? It makes things more difficult. Low oil pressure could be pump is worn or main bearings.
Nevermind it’s an internal pump and it’s on the pump base. What the oil temp? High temps affect viscosity which will lead to lower pressures. If it is getting proper cooling I would pull the pan and change the pump.
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I found the below YouTube link about 4 hours ago but didn’t want to give the O.P enough information to screw a bunch of things up. Sometimes a little knowledge is more dangerous than none. Actually I was going to recommend he change the sensor & call a technician if the problem persisted. But since you mentioned the oil pressure relief valve, I’ll go ahead & post the simple video I found.
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For shizzle…
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FYI:
These guys are a good source of Perkins info and parts.
One thing to check is if the right alarm sensor is fitted. I have seen them at 1 PSI, 3 PSI, 5 PSI, and 20 PSI. I am sure there are others too.
You should probably call the port engineer or a tech instead of asking a bunch of dipshits who’ve never laid eyes on your engine.
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Unfortunately that can often be one and the same.
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I haven’t posted for a bit so i’ll fill some space. Shipengr and sand pebble probably identified the issue, BUT…… as we all know it’s probably something else , hahhhahha and Rafterman could be more considerate?
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Thanks
What do you plan to calibrate? Does your boat use a digital alarm and monitoring system?
If it does there is most likely a user adjustable alarm range and delay settings.