Oil Pressure Question

[Tommyd13]

When my 2005 Mariah sx19 with a 4.3 Merc is in idle the oil pressure is normal at 40 on the gauge. When I throttle up it moves to 80 and stays at 80 until I go back to idle or idle in gear. This boat is new to me so I dont know how it normally is just how it was normal to me. Is this something I should be worried about? I changed the oil when I bought it to 10w30 conventional and changed the oil filter to a wik and not a merc one. There is a ticking sound at idle but when throttle up and run at 3900 rpm+ there is no tick? I was going to put 2 quarts of Lucas Oil in it to thicken the oil a little to see if it helps with the ticking sound but am worried about the oil pressure. Can anybody lead me in the right direction?

 

[H20Rat]

Somewhat normal for new oil that is cold, and dash gauges are notoriously inaccurate. Don't add anything, 10w30 is fine, and if you have an internal engine problem, no snake oil is going to fix that.

Assuming you are throttling up when it is in the water? Hopefully not on a hose.

 

[alldodge]

Put a mechanical gauge Tee'd with the electrical to see what the pressure actually is

 

[Scott Danforth]

the ticking could be the flappers or the balance shaft

the oil pressure should be about 70 psi (stock spring in oil pump). as AD stated, put a mechanical gauge in it and look.

 

[Tommyd13]

Will have to call in some of my mechanic friends for that. I will see what it is. I am a carpenter by trade. If it is the flappers or the balance shaft how serious of an issue is that?

 

[harringtondav]

I changed the oil when I bought it to 10w30 conventional and changed the oil filter to a wik and not a merc one. There is a ticking sound at idle but when throttle up and run at 3900 rpm+ there is no tick? I was going to put 2 quarts of Lucas Oil in it to thicken the oil a little to see if it helps with the ticking sound but am worried about the oil pressure. Can anybody lead me in the right direction?

Read the PDF below for Merc's oil viscosity recommendations. This came from their 4.3 engine manual. Anything 30w seems a little light unless you are operating your boat in a very cool climate. Also read the paragraph on overfilling your crankcase. Lifter noise and oil pressure fluctuations are a symptom. My 4.3 takes 4.0 quarts.

View attachment Oil temp chart.pdf

 

[Tommyd13]

Oil level is just fine. It’s on the line. I pulled out some of the old maintenance paperwork the previous owner gave me and back in 2011 it made the noise according to the paperwork and said it was just the flapper.

 

[Scott Danforth]

I would suggest pulling the flappers and looking at them. The rubber could be burnt off of them. You will want to get the upgraded flappers at that point.

 

[Tommyd13]

Ok I have done a little research and am trying to find a schematic on where the flappers would be. I cannot find it. Any help would be great. Also, we are planning on taking the boat out this weekend would/could do any damage to the motor? I mean this has been going on since 2011 from what the paperwork says.

 

[alldodge]

We don't know what the noise actually is, so there is no way we could estimate damage IF any would occur. If its the flappers (item 7) nothing would happen and they are located just below the exhaust elbow in the Y-pipe. Being its a 2005 I don't see the old rubber coated metal ones ever being installed

https://www.mercruiserparts.com/bam/subassembly/31501/11705/270

 

[Tommyd13]

I have officially found out that it was the flappers. As for the Oil Pressure payed close attention to it today and was right at 75. My Dad always said have of life is paying attention and the other half is showing up.