oil pressure

[mervdog]

I changed the  oil in my M25XPB as usual. I was out sailing, then motoring as the wind died. The oil pressure was fine until I pulled into the marina and dropped the engine speed to idol and my oil pressure dropped. Is this normal and I never noticed it or should I be looking for something. I check the oil when I got in and it was full and I could not find any leaking oil.

[Stu Jackson]

Can you be more specific?  "Oil pressure dropped..."  From what to where?

[Craig Illman]

What weight oil are you using? A multi-weight (15W-40) or a single weight oil (30W)? An oil analysis kit is relatively inexpensive, around $25, and can identify if there are any issues, like fuel dilution. A light weight oil, hot and at low RPMs could easily drop oil pressure down to where the alarm could sound.

Craig

[mervdog]

The alarm did not sound. Using a multi weight oil from West Marine. Not at the boat so I am not exactly sure of the weight. The oil pressure dropped from 50 to about 30

[Ken Juul]

Nice to have an oil pressure guage.  30psi is ok, plenty to keep the engine lubed.  At idle I would worry if it was approaching or below 10-15.

[Ron Hill]

Merv : You might want to check and see if your alarm sounds when you start the engine.  As Ken said 30psi is more than enough.