replacement oil pressure sender

[stg44]

I just replaced the oil pressure sender on my '97 Mercruiser 7.4L Gen VI MPI engine because I believe the internal diaphragm was leaking on the old one. (Old one would read 40psi @ engine start & slowly drop to ~5psi over 10 mins. Shut off engine & restart & it would jump to 20psi & slowly drop down again.)

Anyways, installed replacement & when ignition is turned on (engine off) the gauge is reading 30 psi. After engine start it reads 70psi (subtracting the 30 it started at would be the correct 40psi that it should be at). Is it possible the new part is defective?

The Merc part # is 815425T, but the local parts place only had the Sierra replacement #18-5899. I doubt that it matters, but thought I would note it.

Thanks.

 

[Rat Capri]

Re: replacement oil pressure sender

sounds like the wrong sending unit, there are different resistance specs for different gauges.The majority of boat gauges use VDO type sending units

 

[stg44]

Re: replacement oil pressure sender

Yup, it was the wrong model. The parts guy showed me the box of oil pressure senders & I said "I'll take the one made in the USA" rather than the one made in China (the correct one). Fortunately, I was able to swap them & now it appears to work fine.