piece of sh** oil filters can do that even brand new ones. Try a racing wix. you'll see a diff. on the gauge compared to a reg purolator/fram/etc

I do run the top of the line wix filters on the boat.

I tried swapping senders and gauges with the motor with the questionable oil pressure, and the problem continually stayed with the motor....so i'm thinking its the motor. I might do the mechanical gauge to just be sure, but I'm doubtful its gauge related.

+1 on the filter, a jumper lead to the other motors temp sender wire will eliminate gauge and harness questions. double check oil lines for sharp bends, but sounds like you'll be doing a motor soon.

Darko. Stop messing with senders and gage problems. Install a mechanical oil pressure gage(40 bucks from the zone) and you will know if it has a mechanical issue or electrical issue.

As far as sludge..... There is not any from the original owner. that i can say 100000%

Do you know that there is two sending units ? Did you change the right one ?

+1
That can take the guesswork out of it being electrical or mechanical.

+1
You could be swapping the alarm sender and not the gauge sender. When mine was a factory 502 the alarm was in the bellhousing area and the gauge sender was in the oil filter pad area.

2???? where are they at? I saw 2 bell senders with 2 wires going to them right next to the oil filter housing at the back of the motor


I also had someone tell me to replace the breathers on the valve covers. He said once they get saturated with water they can wash out the oil and cause the issue i'm having. Maybe one of the reasons a fresh oil change gets rid of the problem.

As others stated there are two sending units, one for the alarm system and one for the gauge. Make sure you are swapping the correct one. USUALLY the bell is larger on the gauge unit.

What you are describing sure sounds like a sending unit. Mine did that earlier this year and a new sending unit fixed it.

If it doesn't follow the sender then get a mechanical gauge on there.

As Fixxer22 said... The one on the back top of the motor is the alarm. The pressure sender is on the side of the motor down by the oil filter pad.

The sender changes its resistance to ground with changes in pressure a volt ohm meter can rule out any bad connections... or take the wires of both motors and swap them with a jumper and see if it changes