Fuel/Oil being expelled out exhaust

[Nicholas_AK]

I have a 2005 DF140 that is expelling fuel/oil out of the prop (underwater exhaust). I have verified that the fuel/oil is coming out the prop by putting a bucket under the prop while the engine is running on muffs (boat on the trailer). I replaced the thermostat (which was stuck open) and the poppet valve (which looked fine). These did nothing to solve the issue. I have pulled the vent line on the VST while the engine was running as I was told that a stuck open VST needle would create this issue. However, nothing came out the vent line while the engine when pulled while the engine was running. The spark plugs show no sign of rust, though they are pretty black on the ends. I tested the compression, got 175,170,170,165. I have attached a pic of the dipstick (with the oil level indicated by the red arrow) and the board underneath where I have been running it. The fuel/oil sheen definitely has a significant percentage of oil given that sheen doesn't dissipate immediately. Also, I could see black goblets suspended in the water when I collected the water out of the exhaust.

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[redlowrey]

Disconnect the oil cooler and plug the lines, it sounds like it has failed, or you can run some clear hose off the cooler and you will see the water in it if it has failed.

[redlowrey]

Disconnect the oil cooler and plug the lines, it sounds like it has failed, or you can run some clear hose off the cooler and you will see the water in it if it has failed.

I meant to say you will see the oil in the water through the clear plastic.

[Nicholas_AK]

So take a piece of hose and connect it to each nozzle on the oil cooler? The schematics indicate there are two. We currently have a snowstorm rolling in, so it will be a few days before I can try this.

[Ole Joe]

Nicholas,

Here is some reading for you during the snow storm. Cleaning up the corrosion and replacing the o-rings completely eliminated my problems.

https://www.suzukioutboardforum.com/...-crankcase-oil

https://www.suzukioutboardforum.com/...l-cooler-leaks

Ole Joe

[redlowrey]

So take a piece of hose and connect it to each nozzle on the oil cooler? The schematics indicate there are two. We currently have a snowstorm rolling in, so it will be a few days before I can try this.

I think as soon as you remove the hose off the cooler you will see oil droplets in the water coming out of the cooler, do this, it will be easier for you see what is going on, just remove the hoses off the cooler and plug them, start the motor up and you will see oil coming out of the cooler, it may take a few minutes depending on how much corrosion there is, use the warm up leaver so it is idling high that will bring the oil pressure up as well.

If your engine has never had the oil cooler replaced, just put a new one on, don't waist your time putting an o ring kit in it, you will struggle just trying to get it apart if you haven't done it before, a lot of the time the corrosion is where the o ring sits.

[Nicholas_AK]

I think as soon as you remove the hose off the cooler you will see oil droplets in the water coming out of the cooler, do this, it will be easier for you see what is going on, just remove the hoses off the cooler and plug them, start the motor up and you will see oil coming out of the cooler, it may take a few minutes depending on how much corrosion there is, use the warm up leaver so it is idling high that will bring the oil pressure up as well.

If your engine has never had the oil cooler replaced, just put a new one on, don't waist your time putting an o ring kit in it, you will struggle just trying to get it apart if you haven't done it before, a lot of the time the corrosion is where the o ring sits.

I hate to ask what seems like a basic question, but for my understanding, one of these nozzles is an inlet for water to enter the oil cooler and the other is an outlet? So with a properly operating oil cooler, you would see only water from these nozzles.

[Nicholas_AK]

I think as soon as you remove the hose off the cooler you will see oil droplets in the water coming out of the cooler, do this, it will be easier for you see what is going on, just remove the hoses off the cooler and plug them, start the motor up and you will see oil coming out of the cooler, it may take a few minutes depending on how much corrosion there is, use the warm up leaver so it is idling high that will bring the oil pressure up as well.

If your engine has never had the oil cooler replaced, just put a new one on, don't waist your time putting an o ring kit in it, you will struggle just trying to get it apart if you haven't done it before, a lot of the time the corrosion is where the o ring sits.

As soon as I pulled the hose off, it was full of milky oil. I didn't start it up, because it would seem to me that this is the issue. How else could oil get into the cooler? I'm going to order a new assembly.

[Nicholas_AK]

I wanted to write a follow up and say thank you for the accurate and quick advice. It took a bit for the remaining oil in the water cooling tubes to work itself out, but after a while there was no remaining oil. Aside from draining the oil and having to do an oil change, this job was like 5-10 min if you have a deep 24MM socket to remove the oil filter stand. Ole_Joe -- the mating surface behind the oil cooler was in fantastic shape. I'm assuming one of those o-rings inside the oil cooler failed. For anyone who might come across this, I did contact Brown's Point about the appropriate torque to use when screwing the oil stand filter. They told me it was 4N or 29ft lbs.