Water or fuel in oil / what to look for

[havewill22]

I have a 2006 AR230 with the twin MR1. Backstory: got the boat in December 2023, took it out a few times after fixing a lot of issues not engine related. (Was able to track down the original owner which is about 3 owners before me. Found out that he rebuilt the port engine with a sbt block about 8 years ago, I've heard horror stories using sbt. He said the engine compartment flooded and hydro locked the port engine. I do have an issue with the port engine but it can wait til after I fix the starboard engine). Sat for a few months to do upholstery, marine mats, and paint. Did an oil change as well. Took boat out 2 weekends ago to the sandbar, probably a 15 minute ride, engines seem fine til I reached the sandbar and slowed down to idle speed. Starboard engine temperature light came on and didn't catch it in time but it was either steam or white smoke coming out of the pee hole. Figured it was because it was idling and couldnt pick up enough water but port engine was running fine. Shut engines off and hung out for a few hours. Both engines started back up and rode back to the dock just fine. Checked oil when I got home and it was good.

Fast forward to last weekend, took the boat out to the sandbar again and both engines we're good, no temperature light and didn't notice anything out of the ordinary. Hung out for a few hours and when it was time to go, starboard engine wouldn't start. Good thing I have valves installed on the coolant line, ran with the port engine back to the dock. When I got home, checked the oil and it definitely looked like it had water mixed into it.

Was busy so it sat for a week til today, wanted to look around the engine and check before I decided to pull it. Took the oil cooler off and the oil didn't look like it did last week, wasn't milky, I know it was sitting and could've settled. It now has a really strong fuel smell. I tested the injectors with YDS and all 4 injectors clicked as it should, didn't remove and ohm checked it yet. I removed some of the oil into a glass and will let it sit for a bit to see if there's separation.

If it's not water but fuel, other than fuel seeping through piston rings, how else would fuel get mixed in oil? (Also will do a compression check and leak down test later)

I've read on other posts that injectors could test fine but when engine is running and idling, a injector could be stuck open or at any other rpm range. If it is indeed fuel in the oil and not water, I plan to swap ecu to the port engine to see if fuel gets mixed in to the oil and vice versa with the port engine ecu.

If it is water, I plan to pull the engine to inspect block, exhaust manifold, etc. Could it be both fuel and water?

Picture of oil in glass jar is when I sucked it out and only been sitting for a few minutes. Will wait a few days to see what it looks like. Picture of oil in engine is after the boat sat for 7 days.

Any input would be appreciated, I've read lots of threads on this forum regarding water or fuel in oil but wanted to start my own thread for further tips and advice. Happy Father's day!

 

[Acard7]

The overheat you had probably was just something was sucked up, cavitated, and your intake screen was affected hampering your cooling system, at idle you may not notice there’s something in the pumps. When I sucked up a few things at different times while at no wake speeds I didn’t know I did until I throttled up and then I could feel the vibration and loss of power.

When you say the starboard wouldn’t start, did it turn over at all? Or just turned over and didn’t fire up?

The oil in the jar looks suspect, but be interesting to see how it looks when you post another pic..

 

[havewill22]

The overheat you had probably was just something was sucked up, cavitated, and your intake screen was affected hampering your cooling system, at idle you may not notice there’s something in the pumps. When I sucked up a few things at different times while at no wake speeds I didn’t know I did until I throttled up and then I could feel the vibration and loss of power.

When you say the starboard wouldn’t start, did it turn over at all? Or just turned over and didn’t fire up?

The oil in the jar looks suspect, but be interesting to see how it looks when you post another pic..

It would turnover but not start, on that day when I got home, I was able to start it by finessing the throttle but didn't keep it running any longer than 10 seconds in case it wasn't getting lubrication.

 

[Babin Farms]

Does the oil smell like gas?? Pull the spark plugs and crank it over with the lanyard pulled and see what blows out of the cylinders. Hard to tell if the oil in the jar is aerated or has gas/water in it.
When were the spark plugs changed? When was the oil last changed?

I stick my head over the side of the boat making sure the pissers are working as they should while underway probably enough to make people think I’m crazy. I also like to hear the engines while underway instead of cranking the radio up. Always listening or feeling for something that’s not right.

 

[Acard7]

I stick my head over the side of the boat making sure the pissers are working as they should while underway probably enough to make people think I’m crazy.

I will join the crazy club with you as I look numerous times while underway. 🫡

 

[havewill22]

Does the oil smell like gas?? Pull the spark plugs and crank it over with the lanyard pulled and see what blows out of the cylinders. Hard to tell if the oil in the jar is aerated or has gas/water in it.
When were the spark plugs changed? When was the oil last changed?

I stick my head over the side of the boat making sure the pissers are working as they should while underway probably enough to make people think I’m crazy. I also like to hear the engines while underway instead of cranking the radio up. Always listening or feeling for something that’s not right.

Yes the oil does smell like gas, I'm only second guessing because a week ago, the oil was milky and almost like a shake with very light brown color. I'll do a compression as well as pull spark plugs and crank it when I have some free time.

Oil and spark plugs were changed in February. I'm also the same, when I'm underway, I constantly check for water coming out the pissers.

 

[Babin Farms]

I will join the crazy club with you as I look numerous times while underway. 🫡

Doesn’t help if they're on that the dummy lights are too small, the wrong angle to see & always have a glare on them. Yamaha’s engineer must’ve been about 3.5ft tall when standing at the helm deciding on placement of the warning lights.