4JH-2TE oil sender Passage 42

Ralph Johnstone · Feb 13, 2023

Sensor resistance must be matched to your existing read out for correct pressure reading. Available at any auto supplier. The threads will be 1/8" NPT. Invest in a 1/8" NPT tap (about $10.00) and rethread.

Use caution to ensure all cuttings are removed.

Ralph Johnstone · Feb 13, 2023

Almost forgot, always start at the beginning.

Which is shot, the sensor or the read out and why do you say so ?

dlochner · Feb 14, 2023

Yikes, I just looked up the price for that part at one supplier, ~$150! I have the 3 cylinder version of that engine, a 3JH2e. Have you tried Neimiec Marine, they usually have the best price for Yanmar parts.

https://niemiecmarine.com/

RoyS · Feb 14, 2023

There are adaptors available for that. Get a steel one for strength. Most senders are 1/8" NPT and your engine is probably 1/8" BSP. You will also need a thread sealant but there is controversy over that. The issue is whether or not the thread sealant will affect the electrical ground between the engine block and the sender body. My Yanmar engine manual calls for a sealant while my sender manufacturer (VDO) calls for no sealant. I suspect that the ground will not be affected as there should be some metal to metal contact in the threads with the sealant only filling the gaps. Permatex 56521 is specifically made for sender threads. Check with OHM Meter after installation.

RitSim · Feb 14, 2023

When I had my Universal diesel I found equivalent parts at the Kubota dealer. They couldn't look up marine parts but if I brought them the part number, they could get it. I looked up "Yanmar equivalent" and saw that John Deere has been using Yanmar engines since the 70's. Then looked up "John Deere oil pressure sender". You would still have to do the final detail checking but the price is about $50. BTW, the Kubota threads are not standard US pipe thread. However the threads are very similar and it was easy to make a mistake and cause a bigger problem with the block. So check carefully.

this may be helpful

Upgrading Yanmar oil pressure gauge and sender - Ocean Navigator

While crossing the bar on the Clarence River in New South Wales, Australia, in 2007, the reading on our oil pressure gauge dropped to zero.

oceannavigator.com

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Ralph Johnstone · Feb 14, 2023

juznip said:
Sensor as the resistance does not change from engine not running to engine warmed up. I am assuming thats how it works?

Exactly.

Stay away from marine stores on this one and go to an automotive store. Everything else that goes into or on to my engine is genuine Yanmar (except for oil and oil filters). I seem to remember the Yanmar sensor being even more 20 years ago when I installed my automotive sensor. The sensor was not going to affect the engine whether it worked or not so no harm. The sensor has only lasted 20 years so far but it's still hanging in there.

RoyS said:
There are adaptors available for that. Get a steel one for strength.

Interesting what @RoyS mentioned. Couldn't find an adapter back then and a quick look didn't send anything that glared out at me now, but I bet there is such an adapter in this day and age. Well worth the hunt.

Ralph Johnstone · Feb 14, 2023

juznip said:
I Also found this potential candidate: Oil Pressure Sender for Yanmar Diesels perhaps the best of both worlds, no adaptor required.

juznip said:
Any advice? Boat bucks are in short supply.

And now you're well over $100.00 CAN with exchange rate, shipping, and taxes. Win the lottery or come into an inheritance

? ? ?

Stick with the adapter. Check your max. oil pressure.