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TAMD-41A lost oil pressure

DBaines

New member
New boat to me...2hrs of operation later on 1989 TAMD-41A with 450hrs. Engine was operating with 45-60 oil pressure. Alarm went off and noticed oil pressure on gauge was zero.
Shut down engine immediately and towed in. Verified both gauge and alarm were operating properly - no false alarm. Removed the oil pressure sender and started engine. Oil came out in spurts but not high pressure and smooth like a geared pump. Is it more like the problem is with the oil pump, oil pick-up to the pump, or possibly the oil filter relief valves. Or.....? Very depressing after perfect survey and sea trial.
 
is all the oil still inside the motor? pump and relief valve (there is only one) is in the oil pan. Engine needs to be pulled out to inspect, I would not run the motor until you verify what is causing the low oil pressure. Great thing you still had working warning system on the dash, otherwise you would have cooked few cylinders before realizing whats going on. where are you located??
 
is all the oil still inside the motor? pump and relief valve (there is only one) is in the oil pan. Engine needs to be pulled out to inspect, I would not run the motor until you verify what is causing the low oil pressure. Great thing you still had working warning system on the dash, otherwise you would have cooked few cylinders before realizing whats going on. where are you located??
We overfilled the crankcase with oil and the oil pump started working giving 30-60psi. Our conclusion is the pick-up tube to the oil pump either has a crack or has started to become loose from the oil pump. In either case we are hauling the engine out for inspection. Thanks for your response
 
Pulled engine and the pick-up tube is fine. what next? Oil pump? Kinda unusual I've been told for only 450 hrs but it is a 1989 engine. Any other thoughts?
 
Check/replace oil pressure sender, and while removed hit the threaded opening in the block with compressed air to clear out any debris that might be clogging it.

I would also inspect pump, take it apart its easy, and look for wear marks on the sides of the case where two gears spin
 
Out of the oil sender hole oil should shoot out 40ft under 80PSI at startup. If you are only getting sporadic squirts, you have air leak in the suction side. Everything before pump is suction, and after pump is pressure. So it goes like this:

Long pickup tube (suction)
Into oil pump (suction)
Out of the oil pump (pressure)
Past the pressure relief valve (pressure)
Into the twisted tube (pressure)
Up into the block (pressure)
Into oil filter bracket (pressure)
Etc...
 
Out of the oil sender hole oil should shoot out 40ft under 80PSI at startup. If you are only getting sporadic squirts, you have air leak in the suction side. Everything before pump is suction, and after pump is pressure. So it goes like this:

Long pickup tube (suction)
Into oil pump (suction)
Out of the oil pump (pressure)
Past the pressure relief valve (pressure)
Into the twisted tube (pressure)
Up into the block (pressure)
Into oil filter bracket (pressure)
Etc...

Pick-up tube looks fine as well as the pump. When I filled it with oil to overfull, it had oil pressure so the pump seems fine. Pick up tube had a very small section that was slightly dry on the o-ring so that seems the only possibility. wish there was a real smoking gun. Part comes tomorrow. If need be, will run it with oil pan overfull....
 
Pick-up tube looks fine as well as the pump. When I filled it with oil to overfull, it had oil pressure so the pump seems fine. Pick up tube had a very small section that was slightly dry on the o-ring so that seems the only possibility. wish there was a real smoking gun. Part comes tomorrow. If need be, will run it with oil pan overfull....
Wow...only replaced a barely suspect o-ring seal between the oil pump and pick-up tube. did not look very bad at all but after replacing it, all is fine!
 
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