2011 Nissan 25HP 4 Stroke EFI Oil Warning Light and Alarm

[koehler7@gmail.com]

Hi there,

I have a Nissan 25HP 4 Stroke EFI that keeps sounding the oil sensor alarm. This happens in very different scenarios and there does not seem to be a pattern to it, low speed, high speed, tilted, not tilted, cold and warmed up.

I changed the oil and filter and ensured the levels were good but I am still getting this problem. It is exceptionally intermittent.

Any suggestions on what I can do to diagnose the problem or a fix I should try first besides testing the pressure? Should I replace the sensor? Replace the oil pump? Something else? If I replace the entire oil pump assembly would that cover everything? I'd rather fix it in 1 fell swoop as I want as little down time as possible as my cottage is boat access.

Thank you in advance.

Ben

 

[Sea Rider]

Are you using the correct dino W10-30 grade oil, was oil level found higher than max level when doing so ? Try a new sensor, see what happens.

Happy Boating

 

[pvanv]

Either the pressure is low, or you are getting a false reading. I would install a mechanical gauge on the motor to determine which situation you have. If the actual measured pressure is OK, then you likely have a bad sender. If the pressure is actually low, you have a mechanical problem. Odds are it's a false low, so the probability is that it is a bad sender

3H6076110M

SWITCH, OIL PRESSURE

$16.98

The sender is the least-cost part to change, both from parts cost and it's a lot less labor than ripping down the motor to check the oil pump. Only way to verify for sure is to install a mechanical gauge.

 

[koehler7@gmail.com]

Thank you Sea Rider and pvanv, I appreciate you taking the time to respond with your insights. I changed the oil and filter and ensured it was at an accurate level and I did use 10W-30.

How is the sensor changed? I've ordered the service manual and will know more once I receive it but I am curious how difficult it is to change and where it is located. Also, to check the pressure what type of pressure gauge is required? What is the ideal pressure I should see if it is working as it should?

Again, many thanks in advance for your help and insights! That's what make these forums so great!

 

[Sea Rider]

You're welcome, that's what the Iboats Tohatsu Forum is for. Assume sender/sensor should be located around oil filter, something that protudes out crankcase, a screw type part with attached electrical wire.

Happy Boating

 

[koehler7@gmail.com]

Thanks again. pvanv or Sea Rider, can you confirm the part number you referred to is accurate, just want to be sure before I buy it, also any advice on testing the pressure? 3H6076110M SWITCH, OIL PRESSURE$16.98

 

[pvanv]

The part is correct. It screws into a 1/8" NPT fitting. See the parts catalog. Any test gauge that screws in will work.

 

[koehler7@gmail.com]

I've ordered the sensor and will replace this regardless but while I am at it I want to check the pressure to be sure. Where should I connect the guage to to assess the pressure? Where the sensor is screwed in? What should the pressure be to be considered working fine? Many thanks in advance again.

 

[Sea Rider]

Pressure gauge hose terminal screws direct on sender fiting, don't have at hand factory stated pressure as don't work with 4 strokes engines, Paul probably can provide a proper answer for that issue. But before investing on a pressure gauge assuming you don't have one, better wait till new sender arrives, change it and test OB on water to check if it's the culprit.

Happy Boating

 

[koehler7@gmail.com]

My brother is a HVAC mechanic and has a guage and fittings to make it work, hoping someone may know what the pressure range should be. I've also ordered the servica manual but it has not yet arrived. Anyone know the pressure range?

 

[pvanv]

The oil pressure is similar to a car motor oil pressure. The light will be ON below about 4 psi, and a cold-ish motor will probably have over 40 psi at higher rpm.

 

[koehler7@gmail.com]

Quick update to my problem, replaced the sensor and tested the pressure, pressure is there and I am still getting an alearm. Local marina asked if I had purged the lines? NOt sure what is meant by this? Any thoughts on whaty else to check and what is meant by purge the lines?

 

[Sea Rider]

Purging the lines means passing fluids or air, sort of getting rid of an obstruction or air build up on any fuel, oil line.

Happy Boating

 

[koehler7@gmail.com]

Another update, I spoke to a Tohatsu dealer and he asked aboiut the oil I used, I used the right viscosity but Quaker State automotive oil, he indicated that this could quite easily be my issue and to do a full oil and filter change again but using marine oil. Any thoughts on if this could actually cause my issue?

 

[pvanv]

The preferred oil for that motor is 10w-30 type FC-W mineral (non synthetic) oil. The NMMA rating of FC-W means that it has anti-foaming and anti-corrosion additives. I doubt that automotive oil would cause such a low pressure.

 

[koehler7@gmail.com]

Changed the oil to FCW marine oil, changed sensor and now the alarm only happens coming out of the hole, any other ideas? How would I troubleshoot the wiring/ECU?

 

[pvanv]

Grounding the wire causes the indicator lamp to come on. If the wire grounds during acceleration, that could cause the lamp. Also, verify that the oil is not above full, as foaming can cause a drop in pressure.

 

[koehler7@gmail.com]

I seem to be having not the greatest luck with this lately. When running it the other day the screw that holds the throttle/tiller handle on fell off and I can;t find it in the boat. I've also left my manual at the cottage and don;t have the ability to look the part number up. Would you happen to know the part number or the size and thread of the screw/bolt?

 

[koehler7@gmail.com]

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[pvanv]

9218030525M

SCREW (10 MULTIPLE)

$0.90