Water in oil 2007 AR210 help!!

[Nikokrzynowek]

Back story on the boat. Just bought the boat a month ago. Was told it has been sitting since 2018 on a trailer and hasn’t been touched since. Prior to that the boat was moored at a marina on a fresh water river. The end of the season of 2018 the owner was having issues with one engine getting rpm up, said he believes the Intake grate just needed to be siliconed. Pulled apart both, ended up doing new impellers sleeves and bearings. Reassembled then I figured I’d warm up the engines to change the oil and plugs. Checked oil level on both sticks. Oil looked good was just on the low side of the stick. Started the port side engine, turned water on and within a few seconds the oil pressure light came on. I shut off the water supply then killed the engine. Checked the dipstick and it was full of water. I have not started the starboard side engine yet. I figured maybe the boat wasn’t properly winterized and water froze somewhere and cracked something. I believe both engines would have the same issue so today I removed both engines. Attached are photos of port and starboard engines during the dissambly. I cannot for the life of me find anything. I don’t see any visible external cracks on the blocks. On disassembly of the port engine everything was white milky. No water or oil in cylinders. The water ports on the manifold and heads look perfect no corrosion or pin holes or broken spots like I’ve seen here on the forum. No cracks above the starter. Only thing I noticed was when I pulled the oil cooler off the starboard engine the ground flooded with oil with water in. Anyone have any ideas on what could have happened? Where water sits in the engine / cooler if it wasn’t properly flushed for the winter. What typically cracks on these if not properly winterized. Just trying to narrow down where the issue could be before I start spending excessive money at the machine shop to pressure test everything and start rebuilding everything. Thank you guys any info is much appreciated. I’m new to the Yamaha jet boat world. Always had a inboard outboard bow riders

 

[Bruce]

Problems with the pumps would have resulted in high RPMs with low speed.

If the problem was not reaching max RPM then spark plugs were the most likely culprit.

The 210 series does not have high output MR-1s. The max RPM of high output MR-1s should be around 10,200 RPM. Mine will occasionally indicate close to 10,400. I believe the max RPM of your standard output MR-1s should be 8,000.

Are you sure that the water was not in there before you started the engine? Even if the water was on before the engine was started water getting into the engine should be rare. The most common path for water to get into the engine is through the intake.

Since you are so far into those engines you might consider rebuilding as high output. I am not sure which parts are different.

 

[Nikokrzynowek]

To build into a high output would I need a new ecm for more fuel? Bigger injectors throttle body? As far as oil in the water. When prior to starting the port engine I pulled the dipstick, it was at the low mark but oil looked good. As soon as I started it and put water to the engine the oil / water mixture now completly fills the stick. As for the starboard engine im guessing the water was in the oil when I picked up the boat. I’m guessing something cracked over a few winters with having water inside the engine. I know when I removed the starboard exhaust manifold it was full of water. And when I started the port side engine, prior to connecting the hose, a bunch of water came out of the exhaust port on the transom. So I suspect there was water in the system and was never flushed prior to storage. I’m just not super familiar with the mr1’s and now sure where the water sits and where they would typically crack causing water in oil.

 

[Nikokrzynowek]

As far as the plugs they look like they’ve never been changed. But I also found the starboard impeller had a caps stuck to it, impeller was warn and both wear rings had a lot of wear

 

[Nikokrzynowek]

Hopefully someone checks out this thread and gives me some more input. I separated both halves of both oil coolers last night, where the water cools the oil, and there was no signs of oil. So im guessing the oil coolers are not cracked. What I did notice was both oil coolers, even the starboard cooler was full of milky water. I never even cranked the starboard engine over, so I am very confused on why the oil is watery. Trying to figure out my next steps. I’m guessing I’ll probably have to disassemble everything and have the block and heads pressure tested. Anyone know of an easy way to remove the drive coupler without the tool stated in the service manual?

 

[Acard7]

Sorry you’re not getting much luck. Hopefully you didn’t spend too much on the boat since it was a project for sure. If it were me, depending how much work/money the engines will need, I would really try to find donor jet skis to take their engines and drop them in the boat.

The boat has been sitting for 6 years, could it be that due to condensation and oil breakdown that it would turn milky? For what it’s worth, I’ve ran my engines for a solid 2 min before putting them on the hose, never got a temp alarm, now this is after they’ve been sitting overnight at 50-60 degrees, and I’m sure not many would recommend doing this all the time. I do turn them on for 30 seconds to try to keep the water passages dried out. Just wonder if maybe starting them without the hose would’ve produced the same result or not.

I would beg to question if the last owner had the boat towed due to the impeller issues, but you’d have rust in the cylinders due to the water getting in there.. It is quite the mystery you have on your hands for sure.

 

[Nikokrzynowek]

I wish I could just find a smoking gun and know why and where the water was coming from. I hate to do a rebuild just to put the engines back in and have water enter the oil again. There was no visible signs of water in the oil until I had the engine running and put water to it. It has a be a large leak because within seconds the the water level almost filled the dipstick

 

[Nikokrzynowek]

I’m not sure if this is I’ll help anyone identify what I’m dealing with here but I just pulled the head off the starboard engine. I did not start this engine, and after I pulled it I noticed water in the oil. I did not start the engine because I believed the starter might have been bad. It was only clicking and not spinning the engine over. Port side had no problems what so ever spun right over and fired up. Attached photos is when I pulled the head. Looks as if the motor is locked up. Piston is rusted into the cylinder. I noticed 2 valves in this cylinder are frozen open. I figure whatever the reason for all the water in the port engine is going to be the same as the starboard engine. Both heads are going to the machine shop now for a pressure test and valve job, as I dig further into the crank case and start removing pistons and cranks. Port side engine has no stuck valves, cylinder walls look good and clear, just a lot of water in the oil

 

[Cambo]

Most common water in the oil issues are

Cracked block do a search
cracked head do a search
Exhaust manifold breach attached picture
Oil cooler leak

 

[Nikokrzynowek]

Exhaust manifolds look perfect surprisingly. I’ll take some photos shortly and upload them. I’ve searched this forum and Yamahajetboat forum and I can’t find much information of cracked blocked or cracked heads. Most of the cracked block threads I find are external cracks above the starter. I know water was sitting in the engines for the 6 years the boat was sitting unused. When I unbolted the exhaust manifold on the starboard engine it was full of water and when I started the port engine a lot of water came out of the exhaust port at the transom.

 

[Nikokrzynowek]

Update on this. Both engines sent out to machine shop. Block and heads were pressure tested and all held pressure. Currently being bored for oversized pistons. Swapping heads with sbt head exchange program because the rusty engine had stuck valves. I have not pressure tested the oil cooler yet but I disassembled it completely and there was no traces of oil around the outside of the cooler where water flows. I’m at a loss here on how there could have gotten that much water in my oil just by running off a hose for a few seconds. I figured there must have been a large leak but I can’t find anything. Going to start reassembly soon and I don’t want to run into the same problem and have to pull the engines again

 

[Beachbummer]

Engine flood, or exhaust jacket gasket are possible intrusion points that could explain it, and are somewhat compatible with what you have seen.

Just use new gaskets when reassembling (sorry, had to be said, I know you will) and all should be fantastic.

When I did a similar overhaul of my engines, I also replaced the starters. I hope to get another 14 years out of mine

 

[Cambo]

sometimes the block would crack internally

 

[Beachbummer]

He had the block pressure tested to confirm no crack.

 

[Nikokrzynowek]

The exhaust manifold at the engine did not have any corrosion, like I’ve seen on other posts here, and gaskets looked good. I would think if there was a possible water leak somewhere else in the exhaust the pressure would push the water out and water would enter the engine once I shut it off, but the engine was filling up with water while it was running. The starboard engine I figured out. There was an impeller issue and the previous owner drove the boat back to the dock with that engine off, which resulted in water traveling up the exhaust into the motor. After years of water sitting in the cylinders it rusted and locked the motor up solid. I’m guessing water seeped past the rings and water was pushed into the heads which is why the starboard engine had water in the oil. But why would the port engine oil look perfect and as soon as I started the engine and put water to it, the water mixed with the oil. Water is only forced into the oil cooler, head, and block. Cooler showed no signs of oil where the water flows. Block and heads were pressure tested and held pressure.

 

[Nikokrzynowek]

Engine flood, or exhaust jacket gasket are possible intrusion points that could explain it, and are somewhat compatible with what you have seen.

Just use new gaskets when reassembling (sorry, had to be said, I know you will) and all should be fantastic.

When I did a similar overhaul of my engines, I also replaced the starters. I hope to get another 14 years out of mine

Disassembly and assembly, I found nothing at all that would have resulted in water mixing with my oil. New gaskets on everything, both rebuilt and back in the boat. Had them running on the hose for 10 minutes yesterday, just making sure I had no leaks before water test. No issues oil is perfect, just thought I would share

 

[Cambo]

Hopefully the water test is no issue as well. The pressure in the water is much higher than when on the hose.

 

[Nikokrzynowek]

Hopefully the water test is no issue as well. The pressure in the water is much higher than when on the hose.

I hope so. Hopefully have the boat out next week. Still waiting on a chain tensioner that needs to be replaced. I pressure tested everything, and everything held pressure for 2h

 

[Brad_Ct]

Have you taken all the exhaust apart. I was getting water in my oil and found parts 30 & 31 had deteriorated and water from the cooling jacket on the outside of the exhaust was getting into the engine.

 

[Nikokrzynowek]

Have you taken all the exhaust apart. I was getting water in my oil and found parts 30 & 31 had deteriorated and water from the cooling jacket on the outside of the exhaust was getting into the engine.

My exhaust setup appears to be a little different than that, but same concept I believe. For me 14 and 16 are both rubber with clamps. Inner one (16) to keep exhaust gauges in the center of the exhaust and water on the outside. 14 is just to keep the water from exiting the exhaust and entering the hull. I didn’t replace anything with the exhaust except for the 2 (24) gaskets. It didn’t look like there was any there to begin with. But everything appeared to be in very good shape upon disassembly and assembly. I cleaned everything very throughly. Only thing I found was a lot of sand in the water jackets of the exhaust