low oil preasure alarm df300 2015

[redlowrey]

What was the pressure at 3000rpm, did they tell you, a good engine with small clearances in rotating parts, eg crank,cam, gears, squirters, ect would have around 75psi at 3000rpm and around 30 at idle hot. Not knowing what the mid rpm pressure was it is hard to say pressure reg spring, or stuck plunger, or it has popped a plug in the gallery some where, I hope it is a simple fix for you.

[redlowrey]

redlowrey


Both of my 2016 DF300AP's with 140 hours run:
129°f ideling for long periods
148°f at WOT

Should i am worried?

Chris

''''' no mate, what's the water temp.

[redlowrey]

If your oil level is higher than when you filled it up after the oil change,
then you either:
a) overfilled it while topping off the oil
b) your engine is "making oil" what means that fuel is leaking in the oil

If you are sure that you (and nobody else) did not topped the oil level between the last oil change and now, then your engine probably is "making oil".
You can check that if the engine oil has a strong fuel smell and lost it's oily consistence.
Diluted fuel can lead to low oil pressure readings at idle!

You may get a Blackstone Lab's oil sample canister and have your oil analyzed.

Engines making oil is common for engines trolling for long times and cruising back.
The last miles at WOT is good for your engine and can avoid this problem! '''''What ever made you think that an engine could make oil from fuel getting passed the rings, you seem like a bloke that has got a bit of knowledge, tell me, these engines are running that close to stoichiometric that's an air fuel ratio of 14.7 to 1. to people that don't understand, remove a plug and the porcelain on the plug will be a light tannish white colour perfect inside the combustion chamber, do you think petrol in liquid form would get blown passed the rings and the cylinder producing near perfect combustion impossible. The float in the vst won't hold it's level and it fills, instead of vapour being sucked out fuel starts getting sucked out back in to the engine. This is the good part, when you are idling or trolling the vst has more time to fill and go into the engine, when you give it a flogging the level will drop right down to the right float level, the vapour will be burnt off in the sump, and the level will drop, you think you have bedded your engine in, I don't think so.
Chris

'''''''''''

[ChrigelKarrer]

redlowery:
The water temp is:
129°f / 54°C ideling for long periods
148°f / 64°C at WOT
Chris

[barrell]

Just got the boat back from mechanics. Turns out I had a 7 inch long jagged hairline crack all the way down one side of the oil pump. Mechanics says in 16 years he has never seen it before. Oil pressure is now above 80psi.

[redlowrey]

If the engine is still under warranty keep track of the dates, because they never told you what the oil pressure was at 3000rpm, only what it had at idle and you were oblivious of it until the light came on. It may have only had 20 psi for a long time you would not have known, a good sign though if you have now got 85psi.

[barrell]

here you go! note the hairline crack running full length of oil pump. Motor has 350 hours.

[wilbur1]

When that got warm I bet it really opened up.

[barrell]

Ok , Its been two days ive ran it hard since the oil pump replacement and Im no longer making oil. So I have a theory that I have never seen addressed on any readings Ive done on "Making oil". My mechanics checked all the possibilities. They did compression tests. They pulled all the plugs and they pulled all the fuel injectors. They tested everything and could not find a reason 7% fuel content was in the oil. (see test report posted above)
I believe the low oil pressure from the cracked oil pump was creating a vacuum and sucking the fuel past the rings? Or at the very least the lack of oil pressure was allowing the fuel to leak past the rings?

[redlowrey]

Mate going by that last statement, don't give up your day job

[barrell]

Mate going by that last statement, don't give up your day job

Please explain, When the oil pressure was low I gained a quart of fuel in the crank case in 4hours use (new oil) Now that the oil pressure is back to 85psi the oil level has stayed right on the mark after 8 hours use. Zero fuel leakage past the rings. Can you explain why that has happened?

[redlowrey]

Please explain, When the oil pressure was low I gained a quart of fuel in the crank case in 4hours use (new oil) Now that the oil pressure is back to 85psi the oil level has stayed right on the mark after 8 hours use. Zero fuel leakage past the rings. Can you explain why that has happened?

'''''' It defies logic, do you think that raw fuel could get passed the rings in a combustion chamber that is burning nearly perfect, with an air fuel ratio close to 14 to 1 I don't think so. Your mechanic should have said to you it is a waste of time checking the injectors, when they pulled the plugs, they would have seen the plugs a nice tannish to white colour on the porcelain, telling you the engine is running good. As I said in an other post, a fuel injector that is not closing properly would make the cylinder run rich but still function, a failed open injector would have raw fuel in the cylinder, it would not fire and would miss, and would be blowing white smoke out the prop, THEN YOU WILL GET FUEL GETTING PASSED THE RINGS. You are getting fuel in the sump from an other source, have a look on top of the vst on the evap line where the tee is and if one of the hoses goe's to the crank case that is where the fuel is going after it fills the vst. If you idle around for a couple of days I will bet the problem is back. Your theory on the oil pump is a pipe dream.

[barrell]

Thank you very much for the detailed response. I posted because my mechanics are stumped. They expected the plugs would tell them which fuel injector was bad but they all looked mint. Compression test showed 155 pounds on all six cylinders. The lab reported 7% fuel in the oil when the oil pump was cracked. Now I have zero fuel getting into the oil with the oil pump fixed. Coincidence? or is it related?
I use the boat the same every day. Lots of idling over wrecks and trolling along with WOT when conditions allow. I haven't changed the way I operate the boat at all. Im going to put another ten or twenty hours on the oil and send another sample out to Blackstone labs but so far it is staying on the center of the dipstick hole which is where it was filled to ten hours ago. With the pump cracked I had a quart of fuel leak into the crank case in three hours.

[mambakurly]

engine oil pump crack