First boat First 2008 df140 nightmare oil coming out of manifold IAC issues etc.

[rhumbaclave]

We bought our first boat this spring, a tritoon with a 2008 df140 that only has 150 hours on it... I think that is the problem, old engine with low hours, anyway we/I want to salvage the summer and it is going to be rough without your help. We have been to the lake 3 times and have had issues every-time, including the time I tried to jump the starter and burned it up resulting in a tow(that starter has been replaced). Here are my issues after today.

1. Rough idle and will stall and have to raise Rpm's in neutral to get started again. (I do not have the corrosion leak)
2. When speeding up to plan the boat jumps rpm's up and down. Being a new owner I thought I was screwing up the trim and the prop wasn't catching...but no, its the engine.
3. When number 2 happens there is white smoke.
4. There was oil in the water, it looks like it is coming from the intake manifold.

PLEASE HELP ME. I have an appointment in 2 weeks for the mechanic but I would like to solve this before then.

I was thinking about replacing the IAC, before I noticed the oil leak. What would cause oil in the manifold?

[Moonlighter]

Early DF140’s are known to have issues with the oil cooler corroding where it connects to the engine. If you have the knowledge to remove the oil cooler yourself of can find a video that would be a good place to start looking. Not done it myself as my DF115 doesnt have the oil cooler.

[rhumbaclave]

There is no corrosion on the oil cooler. But I did find there is also for sure Fuel in the Oil. Quite a bit. All the oil smells and the dipstick comes out looking overly full and smelling of oil.

[catacom225]

Ok i see you have 2 post!. The corrosion is on the inside of the cooler, just disconnect the little water hoses and bypass the oil cooler, If your getting fuel in the oil and with compression low i would think fuel is getting past the piston rings. My 140 was making oil, turned out it was the low pressure fuel pump on the rocker cover leaking. These engines need to get hot and like to be run hard

[rhumbaclave]

Thank you so much for replying. The thing that is strange about the pressure test is how close they all were? It would be super strange to have all four pistons to fail the same
right? I borrowed the gauge from the auto store so I may try a different one. It looked pretty used. Do you by chance know what size the nut is on the oil cooler? I am
going to have to pick one up that deep.

[briscoe]

I do not believe you have enough hours for oil cooler issue. This sounds fuels related. Did you replace the water separator? The fuel would be the problem! Ten year old fuel cannot be usable, I don't think. I'm not sure that anything can be adied to fix it. Pump out the gas and refill, change, water separator, check low pressure fuel filter (at a minimum empty it) and then drain the VST. The VST has a small screen that gets plugged and makes it run bad, swings in rpm's. Perhaps pumping the bulb a few times and draining will allow large particles out. Otherwise you will need to pull and open it to access the internal filter.

[catacom225]

pull the plugs out and post a photo of them, they will often tell a story .Remove the IAC and have it tested by an auto Electrician , as briscoe said run a seperate tank and fuel line of fresh fuel [ not premium ] and see if there are any changes. I Had a bad IAC, but it still ran ok, just stalled when shifting back to netural quickly, you stated in No 4 there was oil in the water, do you mean water in the oil?

[rhumbaclave]

As you can see lots of residue. When I did an oil change yesterday the oil was so thin with fuel it shot out of the drain hole like water! I spent some time searching for this and someone else had this issue and it was the Low Pressure Fuel pump. I guess it has a rubber diaphragm inside, if it was corroded and damaged it could be the culprit of adding fuel to the oil. Also with this thin fuel oil could get around the rings and could make it smoke? I have a low pressure pump and an iac coming tomorrow. I will start with the pump.

Before i I bought the boat the previous owner had some work down, I tracked down that mechanic and he said he replaced the high pressure pump and hoses and a few other issues with that because of the corrosion. But he did not replace the low pressure pump...I am praying this is it.

[rhumbaclave]

I will be taking the boat our Monday to check for sure but I think the LOW PRESSURE PUMP was the culprit!

[rhumbaclave]

Boat started and idled fine. Pulled out of the Marina and when fine for 20 minutes at 6000rpm’s. After I turned the boy off started it back up I could only get to 3000rpms. So frustrated. And the oil has fuel in it again. What is going on?

1. Wont go over 3k rpms
2. Fuel in the oil.
3. Lower than normal compression