Where did my oil go?

[TheGriz]

I have a 2007 SX230 HO and have owned it since 2017. I am on my 4th starboard engine and original port engine. The original owner replaced ithe starboard engine the first time with an SBT block in 2015 and it lasted until 2019. I replaced it with another SBT engine, but that brand new engine only ran for 30seconds and failed catastrophically. That engine was replaced under warranty i and has about 15 hours on it (I had a kid and it didn't use it much).

7 days ago, I started prepping the boat for the summer (changed the oil, replaced the exhaust blowers, and replaced the batteries). I vacuumed out 3.5-4qts of oil from both engines and refilled both according to the dipsticks, roughly 4qts in each. The starboard engine was hard to start on the hose, but eventually started. Port engine ran like a champ.

I added about 45 gallons of fresh gas and got out on the lake. On the lake, the starboard engine was hard starting, but eventually started, port engine ran like a champ. As soon as I would chop the throttle, the starboard engine would die. I ran the boat about 5minutes between 7-10k RPM, chopped the throttle and the starboard engine died. I had a couple more attempts to start the engine, but it never ran for more than a couple seconds and then it never started again. Engine would turn over just fine. I did make the mistake of trying to run higher RPM (less than 5min) on just one engine, only to learn here that it can cause water to enter the exhaust of the other engine. I tied up at a dock and took a crack at it the next day with fresh eyes. The bilge was full of water. REALLY FULL. The bilge pump removed it all.

The next morning, The bilge was empty, so I am pretty sure the bilge was being filled with coolant water. I checked the plugs and they were fouled. Replaced them on but it still wouldn't start. I made my way to my trailer on one engine running slowly, in no-wake mode. The bilge was really full again, taking forever to drain through the plug.

Got home, started by checking the oil to see if it was milky, only to be surprised that there was NO oil in it all. Put a camera down there just to be sure... NADA. Did a compression check on each cylinder (200, 200, 210, 210psi).

1. Where did my oil go? (Hoping now that it never restarted because of an oil sensor failsafe)
2. How is water getting into my bilge?

I was hoping to get some advice before refilling with oil and checking for leaks. The engine compartment looked about the same before and after (it was a bit of a mess from multiple engine changes).

 

[Bruce]

Is the oil filter loose or damaged? Is there a crack in the block? Either of those should like the oil into the bilge.

Did the oi exit out of the exhaust.

You might consider refilling with oil then running on the hose to see where the oil is going. I would email SBT to get their thoughts in writing first.

 

[dgfreeze]

Continuing on with what Bruce said, is there any indication of oil under the engine? If it leaked out and dripped down, you should be able to see a slick of some kind. It pretty much has two places it can go: External leak that drips down, or getting mixed into the exhaust. Mixed into the exhaust is a two part possibility, in that it could be mixing with the cooling water, or getting burnt in the combustion chamber. (so you could call it three places) If there's another possibility, I can't think of it right now...

 

[TheGriz]

Ok... after a month away, I'm back working on the boat.

• The dipstick in the sump still read empty, so I filled another 3qts of oil and the port engine fired up. I turned on the hose and let it run for about 3 minutes and the engine died:
  - I thought it was good news that the engine would fire up with oil in it.
  
  
• I fired up the starboard engine and turned on the hose... no problems.
  
  
• After the engine died, I checked the oil in the starboard engine. It was now overfilled (all the way to the top of the cap) and milky, so I know I have water in my oil:
  - I'm unsure how water got in the crank case... perhaps from running on the good engine in the water only or perhaps a head gasket? I'm not sure.
  
  
• I vacuumed out as much milky oil as possible and filled with some fresh oil (maybe a couple qts). Engine still would not restart. I pullled all 4 plugs and turned over the engine to see what's in there:
  - Cylinder 1 blew out a large amount of fuel, the other cylinders had a small amount, but #1continued to spew fuel, for as long as I would turn over the engine.
  - Fired the engine and it started right up (without the engine cover). I did not turn on the hose.
  - I noticed that the intake area around the fuel injectors was filling up with milky oil. I vacuumed it out and fired again to see if I can identify where it was coming from. I did this two times, but could not identify where the oil was coming from.
  
  I've got some thoughts and questions:

1. Can water get in the crank case from my lake experience of running on the good engine only?
   
   
2. Head Gasket could be source of oil and water mixing. Could this also be a path for engine oil to get up into the intake housing? The oil up in the intake housing was milky and I wasn't running on the hose... sure there is still water in the system from starting it on the hose the first time.
   
   
3. The overfilled condition could be a reason for oil in the intake, but after vacuuming out the oil, it wasn't overfilled and I'm not running on the hose, so coolant water isn't causing an overfilled condition.
   
   
4. I'm not really sure if there's a PCV valve or similar on this engine, that was my other thought about oil in intake, but not sure that would explain water in the oil.
   
   
   I could use some additional ideas... the good news is that I've determined where my oil went (up and out through the intake housing). Perhaps Intake housing isn't the right word, but it's the area in the picture... the milky oil was flooding the injector area.
   
   Thanks in advance.

 

[CastawayRK]

Let me start by saying I know lots about automotive engines and much less about Yamaha jet drives.
If water and oil are mixing is it possible your oil is going out the pissers? Maybe depending on RPM the oil is forced into coolant or vice versa.
You have (I think) a water fed oil cooler. That is a real common cause of water oil mixing on cars,much more than head gasket or cracked head. Any of which can be the cause.
I have no idea about the fuel out of #1.
The suggestion to contact engine supplier seems on target too.
Good luck!

 

[dgfreeze]

1: my understanding is yes, through the exhaust, and into the combustion chamber of whatever cylinder has open exhaust valves. I forget the exact path that was explained, and I hope I never have to educate myself on it in person. If you’re lucky, that’s all it is. It’ll take a few oil changes if you’re vacuuming out of the sump, or you can perform a full service oil change, which drains the sump also. That’s a bit more challenging, but there have been people on here who have done it, and documented the procedure.

2: the oil in your intake housing is likely a result of it being over-filled. The over full condition over pressurizes the crankcase, and pushes the oil out through the PCV valve, where it gathers around the air filter. Check your air filter. If it’s oily, you need a new one. An oily air filter (of this material) restricts air flow, which will starve the engine for air.

Also something to note that hasn’t been discussed, these engines are a dry sump engine, in that instead of an oil pan like all the engines I’ve ever worked on, they have the reservoir up top for the oil, and the oil pan is “dry”. (Obviously not actually dry, they’re just not designed to hold the engine’s oil). My understanding is that it’s possible for oil to “bleed” down into the sump, leaving the sump low or empty. As I’ve already mentioned, I’m not very knowledgeable on these systems, but I could see it being the case here, since it was empty, and after running, it’s way over full.

Also, with your injector #1 spewing fuel, it’s usually a bad ECU. If you’re lucky, it might be a faulty injector, but these engines are known for their ECU’s getting moisture in them, and holding an injector open. BE CAREFUL. If the spark plugs are installed, it can lead a hydro lock, and literally snap a connecting rod. Also, remember when cranking the engine with the plugs out, and it’s spewing fuel….that shits highly flammable. One spark or backfire, and there’s a huge fireball. I’ve learned a few things the hard way. Now that I’ve cautioned you, swap #1 injector with an injector from another cylinder, and see if the spewing of fuel stays on cylinder #1, or if it follows the injector. If it follows the injector, replace said injector. If it stays on cylinder #1, almost has to be an ECU.

 

[finnrigged]

With your cylinder filling up with fuel, as was stated above, it's going to either be a bad fuel injector relay on your ECU or I have had one of these FX high output fuel injectors just stick in the open position on its own. I replaced it and it is still running today just fine. But before replacing it that cylinder was filling up with fuel so fast that it was filling up the oil reservoir with a gasoline oil mixture. That being said, are you 100% certain that you have water in your oil and that it is not gasoline? You would be able to smell a strong smell of fuel in the oil if it was gasoline. It would also be a cloudier chocolate colored oil instead of a white striped thick gummy oil that happens when you get water in it.

And yes, you're definitely overfilling your oil. When you put an extraction pump of any type down into your oil reservoir and siphon it out you will never get more than about 2.4 quarts of oil out of that Reservoir out of the nearly five quarts of oil in this system. The Yamaha manual specifically States that it is a dry sump system which means that unfortunately you have to actually warm your motor up to operating temperature before you actually test oil level to see if it is correct. When these motors are perfectly level and when it has the exact perfect amount of oil in the system, you should be able to clean off your dipstick, spin it all the way down into the oil reservoir and when you remove it it should literally have less than 1/4" of oil shown on the dipstick on a completely cold motor that has been sitting for a few days.

That boat sounds like a major basket case for problems though regardless.