Need Help with M1 Engines

[Melo]

Hey all I'm new to this forum thanks for all the great info posted so far.

I apologize for the long read ahead of time.

My question is in regards to the 2 M1 engines on my 2006 Yamaha jet boat. The initial problem started in one engine where I noticed a decrease in RPM while out on the lake and when I came to a stop and turned both engines off to float and enjoy the water. Then that engine would not start or even attempt to turn over....

We put the boat back on the trailer and it sat for about 2 weeks before I could look into it and much to my surprise the engine that failed started right up no problem.

I then decided it may be a good time to change oil filters and Spark plugs. When I did so I noticed a lot of oil near the 4 manifolds next to air filter....

Cleaned it all up changed oil, filter, and Spark plugs fired them up and saw no issues.

Took the boat out to the lake once again and (see pictures below) but now both engines are spitting out into the air box a shimmering liquid and smells like gas and oil mixture of some type.

What the heck am I dealing with here?

 

[Melo]

 

[Acard7]

I’m still somewhat new here but maybe you overfilled with oil during the oil change? It is my understanding that when not warmed up these engines need to be at the lower fill line, NOT the “F” line on the dipstick. After the engine is warmed up and level, the oil should then be at the full line marked on the dipstick.

 

[Cobra Jet Steering LLC]

gas smell may be a good indicator that you have a stuck injector flooding the oil with gas but BOTH engines probably not, I did see what looked like water bubbled in one of your engine pictures at the lower right portion of the engine head

 

[Melo]

I’m still somewhat new here but maybe you overfilled with oil during the oil change? It is my understanding that when not warmed up these engines need to be at the lower fill line, NOT the “F” line on the dipstick. After the engine is warmed up and level, the oil should then be at the full line marked on the dipstick.

Ok thanks so I will pull some oil out. I wonder why the engine shuts down though and looses RPM is it a safety mechanism or just the engine can't breath right because of access fluid in air box?

 

[Melo]

gas smell may be a good indicator that you have a stuck injector flooding the oil with gas but BOTH engines probably not, I did see what looked like water bubbled in one of your engine pictures at the lower right portion of the engine head

Ok thanks I will see if I can find a way to clean out injectors. Any idea where the water would be coming from or those bubbles?

 

[Julian]

If you over fill oil, it will blow out onto our airfilter and clog it, starving the engine of air-killing it. Did you fill the oil to the low mark cold on the engines?

But this looks to be something else....like @Cobra Jet Steering LLC says....could be a stuck injector or a bad ECU....but to have both engines do this at the same time...strange.

 

[Cobra Jet Steering LLC]

If you were running the engine with no oil and now it will not turn over it may be blown. can't run these with no oil very long without causing some damage. Also remember the marine engines do have issues with oil filters rusting through and I had one split on me once not even rusted so now I use very strong oil filters , if they flex in my hand forgetaboutit. I have 1800 engines but I use Fram tough guard 3600 filters now, the one that hatched was a new filter. https://jetboaters.net/threads/new-oil-filter-failed-just-did-the-oil-change-2-weeks-ago.18678/ also never run in limp mode stop and find out what is wrong now you did not do that but for the class of 2021 take heed limp mode is NEVER safe mode. Your issue could be a multitude of things pretty difficult to guess. did you try rotating the engine backward using the P T O at the rear of the engine to see if maybe something is just hydro locked or the pump is stuck , remove the plugs if not already done and go to the back of the engine work the P T O coupler back and forth and see if the engine unlocks

 

[Melo]

If you over fill oil, it will blow out onto our airfilter and clog it, starving the engine of air-killing it. Did you fill the oil to the low mark cold on the engines?

But this looks to be something else....like @Cobra Jet Steering LLC says....could be a stuck injector or a bad ECU....but to have both engines do this at the same time...strange.

Based on all replies it sounds like this may be the big issue. I filled it to full while it was cold ( didn't know any better)

I will also run some injector cleaner through it and see if that helps. Thank you for your response.

 

[Melo]

If you were running the engine with no oil and now it will not turn over it may be blown. can't run these with no oil very long without causing some damage. Also remember the marine engines do have issues with oil filters rusting through and I had one split on me once not even rusted so now I use very strong oil filters , if they flex in my hand forgetaboutit. I have 1800 engines but I use Fram tough guard 3600 filters now, the one that hatched was a new filter. https://jetboaters.net/threads/new-oil-filter-failed-just-did-the-oil-change-2-weeks-ago.18678/ also never run in limp mode stop and find out what is wrong now you did not do that but for the class of 2021 take heed limp mode is NEVER safe mode. Your issue could be a multitude of things pretty difficult to guess. did you try rotating the engine backward using the P T O at the rear of the engine to see if maybe something is just hydro locked or the pump is stuck , remove the plugs if not already done and go to the back of the engine work the P T O coupler back and forth and see if the engine unlocks

Thanks man. Appreciate all your feedback...

On that last part you lost me... Limp Mode?

Also what is PTO and no I have not tried that and did isn't even know you could do that. Do you know of any good links to a video or document on how to do that?

 

[WREKS]

@Melo

Ok thanks I will see if I can find a way to clean out injectors. Any idea where the water would be coming from or those bubbles?

The airbox in the photo has a breather hose coming in to the bottom of it. It is located below the blue inked area. Overfilling with oil can force oil through this hose up into the airbox. Being a breather hose it could be bubbling oil saturated air through the oil in the bottom of the airbox. I would just keep trying suck the oil out the bottom of the air box without disconnecting anything.

 

[cybuch]

That looks like water in the oil to me. pull the dipstick and see if the oil looks like chocolate milk.

 

[David Martin]

Gas will make it froth also.

 

[Melo]

@Melo
The airbox in the photo has a breather hose coming in to the bottom of it. It is located below the blue inked area. Overfilling with oil can force oil through this hose up into the airbox. Being a breather hose it could be bubbling oil saturated air through the oil in the bottom of the airbox. I would just keep trying suck the oil out the bottom of the air box without disconnecting anything. View attachment 156480

Thank You! That's helpful.

 

[Melo]

That looks like water in the oil to me. pull the dipstick and see if the oil looks like chocolate milk.

If the dip stick is Milky looking what would be the cause?

 

[cybuch]

It could be either water or fuel. Most likely water, knowing these engines. Smell it does it have a heavy fuel smell?

 

[Dennis P]

Sounds like an ECU issue

 

[Cambo]

That is The dreaded chocolate milk oil most likely what is happening water is getting in the engine it’s raising the volume of oil then spills out the breather this gets all over the air filter then decreases rpm due to the interrupted air flow and that’s what your showing in the picture. When you changed the oil was it light brown like chocolate milk ? Do a compression test immediately and post the results . There’s a bolt on the back of the motor that allows you to drain all the oil do a search for MR1 ( correct label for your motor ) complete oil change. the most common issues for milky oil are cracked block, breached exhaust manifold by cylinder head , flushing engine with motor not running, and oil cooler leak