Oil Pressure

[Boilers2000]

92 4.3lx did an oil change in the fall and filter, ran engine yesterday and oil pressure is topping out at 3000 rpms, probably lower at idle. Manual says 35-55 psi at 2000 Rpms. Anything to be worried about?

Thanks in advance!

 

[Scott Danforth]

3000 RPM is your speed. What pressure are you seeing? And is this with the dash gauge (horribly inaccurate( or a mechanical test gauge

 

[zul]

Keep checking your stick. It is easy to put too much oil in. If you didn't get all of the old oil out, you may have 1-2 quarts too much oil. When cold, I like to read 'Add' on the stick. When running, I like to have 'some' oil on the stick and adjust from there. From my experience, you do not want to be at 'Full' or over Full.

My 4.3L oil pressure reads quite high, 65-70 PSI (normal for me). After running for 1 or 2 hours, that oil pressure comes down a bit (to 60 PSI).

Hope that helps!

 

[alldodge]

The pressure is a reference, and rule of thumb is 10 pounds for every 1000 rpm.

 

[Bondo]

ran engine yesterday and oil pressure is topping out at 3000 rpms,

Ayuh,..... Toppin' out at What,..??..??

On the water, with a fully warmed motor, or on the muffs in the driveway,..??

 

[QBhoy]

Aye. What pressure is it at ?
Obviously it will be high when cold
generally about 40 psi is healthy at low rpm and warmed up. Bit higher up the rpm.
If it’s lower than this when warm...check the oil for fuel

 

[Boilers2000]

All readings where on the water after running from first splash to after an hour of towing and using the gauge. I would say on my dipstick I'm at fullish mark when cold, but dragging a 36" dipstick it feels impossible to get an accurate reading. Any tips on getting a good reading on a boat dip stick...I typically take a clean cloth and roll the stick over to see where oil transfers to the cloth. To clarify I would say I was running between 50 and 60 psi any where from 800 rpm idle to 3500 rpm under way. Should I drain a slight bit or oil. What the best way, pull the plug for a sec? When I did the oil change in the fall I feel like I pulled 6.5 quarts out based on the vacuum pump, and put in about 6.5 pts.

I feel like it wascrunningv60 psi when cold then as the engine warmed up it dropped.

How do you test with a mechanical quage. Is it a gauge that you swap in where the oil pressure sensor goes?

Apologies for the delay in getting back to this question, especially after all the speed responses! Got tied up with work.

 

[harringtondav]

..still a little bit short on info. My 4.3LX takes 4 quarts. One gallon, including filter. My Merc manual #18 which covers '93 >> states minimum (hot) oil pressure at idle 4 psi, 30-55 psi @ 2000 rpm. Your dash gauge readings look good. Oil pressure drops as the engine warms up, increases with rpm. The pressure bypass valve will keep it from getting too high...if working properly.

If your dipstick is +- close to full, don't worry. Too much over full will cause aeration. Not good.

 

[QBhoy]

Mmm. As said. Still don’t really know what you are saying or asking.
Ive had 4 different boats with mercruiser and vp 4.3 engines in them...they all took 5litres of oil changing the oil and filter.
Oil pressure will vary, but usually 40 psi once warm at low rpm. Slightly more up the revs on plane.

 

[alldodge]

To recap
pulled 6.5 quarts.... put back in 6.5 pints (2.25 quarts)
50 to 60 psi from 800 to 3500 rpm
Dip stick flush at full mark

Measurement is sketchy, but since your at the full mark your good

The high oil pressure reads is probably just the gauge or sender. Port side of the motor down low by the remote oil filter connection there is your oil pressure sender for the gauge. There is also the oil pressure switch, both are attached to a Tee fitting. It has a single Light Blue wire on it. Remove the sender and attach a mechanical pressure gauge. Could probably get a loaner for a local auto parts store

 

[Scott Danforth]

All readings where on the water after running from first splash to after an hour of towing and using the gauge. I would say on my dipstick I'm at fullish mark when cold, but dragging a 36" dipstick it feels impossible to get an accurate reading. Any tips on getting a good reading on a boat dip stick...I typically take a clean cloth and roll the stick over to see where oil transfers to the cloth. To clarify I would say I was running between 50 and 60 psi any where from 800 rpm idle to 3500 rpm under way. Should I drain a slight bit or oil. What the best way, pull the plug for a sec? When I did the oil change in the fall I feel like I pulled 6.5 quarts out based on the vacuum pump, and put in about 6.5 pts.

I feel like it wascrunningv60 psi when cold then as the engine warmed up it dropped.

How do you test with a mechanical quage. Is it a gauge that you swap in where the oil pressure sensor goes?

Apologies for the delay in getting back to this question, especially after all the speed responses! Got tied up with work.

If you pulled put 6.5 quarts and put in 6.5 pints, youre low on oil

60 psi is fine on your $3 dash gauge. If you want to know accurate pressure, you need a good mechanical gauge

 

[Boilers2000]

Sorry for the confusion and as usual you guys are on it. I pulled 4-4.5 qts in and added back 4.25 qts back in. Glad I haven't gotten rid of the oil yet since I still have the old in the gallon container. I'm at the fullish mark but damn it hard to get a clean pull. If I wanted to drop a little oil out what is the best way?

 

[Scott Danforth]

most likely you are perseverating over nothing.

 

[Boilers2000]

I’m sure I am...just always on the look out for something looking different or out of whack!

 

[Carver yacht]

I have twin 3.7 merc, one engine stalls shifting g out of forward, the other stalls.shifting out of reverse, anyideas please

 

[alldodge]

Let the motor sit with dip stick out for a couple hours, then put in and have a look
I'm also guessing its nothing to worry about.