Mercruiser High Oil Pressure?

[NatedoggAZ]

Hey all,

Went boating 2 weekends ago and I noticed that the oil pressure was fluctuating between 40 and 80.

I just changed the oil and filter - and this was the first time out since the change.

I'm guessing that possibly the sensor is acting weird...hopefully?

Where is this sensor located exactly and is it a pain to switch out?
Anyone know what part number I may need?

I guess I could also rent/borrow an oil pressure tester from Autozone or whatever to check it out as well - just not quite sure how to do that...

1988 Mercruiser 4.3
Serial Number: 0B847392
Engine model: 443S100AR

Thanks!

 

[greno]

It's possible you have a loose connection.

 

[Bt Doctur]

most times the sender is to the right rear of the dist facing the motor

 

[alldodge]

Being a 1988 the oil pressure sensor will be in one of 2 locations. On top the deck below the distributor or port side down low next to the oil filter or oil filter remote adapter. It looks like a small can type

https://www.mercruiserparts.com/8m0068784-sender-assy-1

Remove the wire and turn the key ON, then ground the wire and the meter should peg high

 

[Scott Danforth]

Could be bad sender, could be sticking pressure regulator in pump, could be spinning bearing.

Install mechanical gauge to verify

 

[NatedoggAZ]

Thanks for all the help so far...

So - are there 2 separate components - a "sender" AND a "sensor"..?
Or are they the same thing?

ND

 

[alldodge]

your motor being a 88, it should only have one sender (can also be called sensor) for the gauge

 

[NatedoggAZ]

Went out to the boat yard this evening and found the pressure sensor/sender - it was right on top of the engine to the right of the distributor and accessible.

The catalog says to go with Mercury 90806:
https://www.boats.net/product/mercury/90806?ref=682ece96460a0047d04608f040d299ff4eb47e05

Or Sierra 18-5899:
https://www.iboats.com/shop/sierra-18-5899-oil-pressure-sender.html

I ordered the Sierra part because it was a little cheaper...should have by Friday to install for the lake on Saturday =)