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AD31B Oil Pressure

hookipa

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"Hello again all,

After 2 y


"Hello again all,

After 2 years of sitting on the trailer I have finally gotten back to trying to fix my low oil pressure issue. Needless to say, time does not heal all wounds.

I am ready to dig hard into fixing this issue and I am looking for a strategy to attack with.

Here are the symptoms:

Takes about 4 seconds to build pressure for alarm to stop.

Engine Cold
Oil Pressure at idle - 30 psi
Oil Pressure at 2000 - 50 psi

Operating Temp (175 F)
Oil pressure at idle - 8 psi
at 1000 - 10 psi
at 1500 - 28 psi
at 2000 - 32 psi

After going on plane for a while the water temp goes up a bit, but still in tolerance. Go back to idle slowly and the oil pressure goes to near zero and the alarm sounds.

Manual states idle hot should be 31 psi

I have checked with a manual gauge and the readings are correct.

I can not reach max rpms with the props I have on the boat (B5) I only get around 3000.

What would be your approach in troubleshooting this problem?"
 
"Either check with a manual P

"Either check with a manual P gauge or replace
sender and see if the issue is corrected.
Check All connections first including the harness plug and sender terminals.
My 2 engines sat 2 years and one registered low and sometimes with the alarm. Sender fixed issue. Decided to replace "working" sender on the 41B and got another 10 PSI with new sender.
If your senders are original, they are almost 20 yrs old. Time to change it out maybe."
 
Sorry caught the fact you chec

Sorry caught the fact you checked with a manual P gauge. Do you get noload 4000rpm?
Did you check air filter and see if turbo is spooling up?
 
"Yes, I can get 4000 unloaded.

"Yes, I can get 4000 unloaded. The turbo spins freely, but I have not looked at it while running. I replaced the oil pressure sender not long ago for another reason, so it is fairly new."
 
"If nothing has changed except

"If nothing has changed except sitting in storage, and it did not have a rpm issue before, then I would look at fuel filters, and slug from
stale fuel. Others have posted suggestions onhow to check for good flow. Can you inspect the inside of the tank? I rinsed mine with a little gas and was amazed with the crap inside I could not see."
 
"What oil are you using?
I us


"What oil are you using?
I used to run 15W-40/50 without problems on mine A's.
As for performance, do a turbo pressure check . Pressure need to be 0.8 at about 24-2600rpm."
 
"I am using 15w-40, which is a

"I am using 15w-40, which is all that is available here. My big concern is with the oil pressure. I think I am propped wrong on the RPM issue. I just put that in with the thought that over loading the engine with the wrong props may have an affect on the oil heating and ultimately pressure. Is it possible that the turbo in some way could cause oil pressure problems? I can't see how it can, but no harm in asking
"
 
Doubt the turbo has anything t

Doubt the turbo has anything to do with the oil pressure.
I'm more 'afraid' you might need to drop the oil-pan and check the screen on the pump-suction tube/pump and pressure valve.
 
"I have somewhat been preparin

"I have somewhat been preparing for an engine removal. I guess once I get to that point I might as well check the bottom end bearings with the pan off. You figure the screen may be clogged, or the pressure relief valve may be weak or stuck open?"
 
"yes. Find it hard that the pu

"yes. Find it hard that the pump itself is toast. Might be a spun bearing, but you will probably not find out until oil-pan is down."
 
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