Oil Pressure issue

[brodie123]

Hi All;

Just installed a new oil pump on a Mercruiser 224 3.7L L4 due to really low oil pressure gauge readings - the motor was already out of the boat.

I have a new oil sensor on it. I realize the gauge and/or wiring could also be bad. It's currently "0" pressure.

Question is, without an oil gauge, is there any way to make sure that the oil pump is at least working? I thought about taking off the oil sensor and hook up some thin hose and check pressure with my thumb.

I seeking for a manual oil pressure gauge but this would be handy to know - especially when out on the water.

thx!

 

[Scott Danforth]

Mechanical gauge is required

 

[brodie123]

Ya that's what I figure. I pulled the sending unit - it feels heavy - maybe a bad diaphragm - I've ordered a new one.

Hooked up a hose and tested with thumb pressure - lots there - at least I know the pump is 'working'.

thx

 

[Bondo]

I have a new oil sensor on it. I realize the gauge and/or wiring could also be bad. It's currently "0" pressure.

Ayuh,.... By groundin' the wire at the sender, with the key On, it should Peg the gauge,....

 

[NHGuy]

You can get a mechanical gauge at most auto parts stores for $20 or $25. It's a good tool for your arsenal. You can prove the validity of the other stuff you have.
Also you can ohm out the sender. You remove the wire, put one probe on the sender terminal and the other one on the sender body. Check before you start it should read 227 to 257 ohms not running and should be less than 162.5 after you start. That's 20 lbs oil pressure or more.

 

[brodie123]

Thanks everyone - manual guage showed good pressure, replaced the oil press sending unit and all is good again.