Water in cylinders

[Twin Spirit]

I put the boat in the water started it up and ran fine for 15 min until I was tied up in my slip. An hour later I started it up again and 1 engine was running rough. I rev'ed it at 2000 rpm to "blow it out" but the temp went up to 200 so I shut it down. After that it wouldn't turn over.

I drained the block and it was still full of winterizing anti-freeze so I replaced the thermostat. When it still wouldn't turn over I removed the plugs and all the plugs had water on them and one of the cylinders water drained out. When i turned it over water would squirt out the spark plug hole. I removed the manifold on that side and inspected it, it seems fine. I plug the drain hole and filled the water jackets with water but nothing is leaking into the exhaust section. The elbow and gaskets also seems fine after inspection. Turning it over with no manifold attached there is no more water squirting out.

Is there something I'm missing? Has anybody heard of water backing up the exhaust?

 

[Twin Spirit]

Well I just drained the oil. The first thing to come out was water!! Is it the intake manifold, the head or the block? It did run perfectly fine for a while.

 

[Bt Doctur]

I put the boat in the water started it up and ran fine for 15 min until I was tied up in my slip

That is more than enough time to change out the AF with water. Exactly how was it winterized?
And dont leave anything out of the way you did it
With the therm housing removed, fill the block to the flange and see if it drops.
Yes means a cracked block

 

[Twin Spirit]

The water level at the thermostat flange hasn't changed in a couple hours. Does it have to be under pressure? If it's a cracked head or blown gasket would it let water into the cylinders and oil pan?

I'll send you my winterizing process when I get home.

 

[Bt Doctur]

No, does not need pressure. if the block was cracked to allow water into the valley or block it would be apparent right away.
So then why wasnt the raw water pump pumping water? Was this motor tested on land before launch?
And if you tell us what motor and what drive it will be easier to give you better answers.

 

[Twin Spirit]

It's a 2002 mx 6.2 mpi with bravo 3. It wasn't tested on land. The fresh water pump was working, it was the thermostat that didn't open up when it reached temp.

Would a vacuum gauge in the spark plug hole determine if the head was cracked or gasket blown?

 

[Bt Doctur]

Not a vac gauge but a compression testing gauge. you need to remove all the sparkplugs and disable the coil so it dosent produce sparks

 

[Twin Spirit]

OK, on my way to buy one.

Thanks

 

[Twin Spirit]

This is how I winterize the engines.

Winterize engine cooling systems, need 32 litres

• Remove drain plugs from exhaust manifolds, cylinder block, fuel cooler, starboard side Y-fitting
• Clean drain holes with stiff wire until entire system is drained.
• Remove both hoses from fresh water pump and drain water.
• Starboard engine remove upper hot water tank hose and blow water thru.
• Turn engine over (do not start) to purge water from seawater pump.
• Disconnect hoses from thermostat housing.
• Check for broken impeller parts.
• Pour antifreeze (propylene glycol) down hose to exhaust manifolds until it comes out the drain ****. Install drain **** and continue filling manifold until antifreeze comes out of the exhaust.
• On starboard engine pour antifreeze down upper hot water tank hose until it comes out water pump drain ****.
• Pour antifreeze down hose to engine water pump until it comes out drain ****. Install **** and continue filling until block is full.
• Pour antifreeze down hose running thru fuel cooler until it comes out the water pickup.
• Install and tighten all hoses.

 

[Bt Doctur]

That reads like it should have been good . water in the pan would have mixed with the oil if the motor was run. If you only found water than it had to go past the rings and into the block when you shut it down.
Sound more like a cracked riser that dumped water into a cylinder described by your account of "rough running" at the next start up.

 

[Twin Spirit]

There was about a cup of water in the oil pan when I drained it. When you say riser do you mean the elbow that attaches to the top of the exhaust manifold?

So if there was water sitting in a few cylinders due to the exhaust when it was running it could have been forced past the rings into the oil pan and blown across the intake manifold to make the other plugs wet?

First thing in the AM I'll be running that compression test.

 

[Bt Doctur]

You would be surprised what and how water gets into things. You most likely have the dry joint system. These next pics came from a similiar motor that was racing another boat. It lost power and stalled. When I got it it was hydro locked from bad manifolds and wore the rings and bores away from the water leakage into the engine over time.
I would remove the hoses from the manifold and drain everything and direct the hoses into the bilge.. Get the motor running for 20 seconds at a time to dry the cylinders.
Remove the riser/elbows and carefully fill from the bottom of the manifold with a hose to the top and let sit You looking for any wetness to appear.
Riser/elbow failure will be readily visable.

 

[Twin Spirit]

I removed the manifold on the side that had the cylinder full of water. Only one port had a bit of rust and that was probably just from waher siting in it for a couple days. I plugged the drain plug in the manifold and filled the water jackets. It sat like that all day and the exhaust ports stayed dry. I did a visual inspection on the elbow and it looked fine. Should I do a leak test on that too? .

I can't run the engine right now but I did turn it over with the plugs out to push all the water out and it's been sitting like that drying for 2 days now. I used a small camera to check the cylinders and there was spots of rust starting to form inside. Should I spray some engine storage spray into them?

 

[Bt Doctur]

whats the inside of the riser look like

 

[Twin Spirit]

Flat black with a few small drops of water dispersed around. It looked like it was just sprayed up from a cylinder or the manifold that had water sitting in the bottom of it.

 

[Twin Spirit]

These are the cylinder numbers with psi for the compression test.
1...180. 2...191. 3...207. 4...214. 5...203. 6...188. 7...200. 8...170.

The engine was cranked over 40 times during the compression test and water level at thermostat flange stayed the same. More proof it's not the block.

Am i correct in assuming if a head gasket was blown 1 or 2 of these readings would be much lower.

Does this test prove a head is not cracked or is that still a possibility?

Could it be the intake manifold. The cylinders near the front of the engine were wetter than the back ones. When I was running it could water in the cylinders have pushed that cup of water past the rings into the oil pan?

 

[Bt Doctur]

I put the boat in the water started it up and ran fine for 15 min until I was tied up in my slip. An hour later I started it up again and 1 engine was running rough. I rev'ed it at 2000 rpm to "blow it out" but the temp went up to 200 so I shut it down. After that it wouldn't turn over.

That opening statement make no sense. I suspect the engine mounted pump was not pumping for those 15 minutes and the motor got hot and something leaked .
the running rough part was water in the cylinders already just from sitting. Double check the raw water pumps impeller .
water dosent really run thru the manifold. water is only present in the 2 most foward ports of the water jacket to get to the thermostat
numbers dont look that bad 90 lbs or less would indicate a possable gasket issue

 

[vetting]

I had a similar issue - it would only fill with water when sitting after it got hot. It ended up being a cracked head in one of the water passages. It would only open wide enough when it was warm.

 

[Twin Spirit]

When I pulled the hoses off the fresh water pump winterizing antifreeze came out of both of them. You can see the condition of the impeller. I managed to find 4 of the 6 missing blades, the other 2 must have made their way into the block. After putting it all together I let it idle up to operating temp and it stayed at 160. Turned it off and ran it again and it purred.

Lesson learned, always, always, always, start em up on land before launching the boat in the spring.

Question still unanswered, how could running with a bad impeller put water in the cylinders and oil pan when it wasn't pumping any water at all. If it's a cracked head similar to vetting's engine I'll find out soon enough i guess.

Bt Doctor, thanks for all your help and advice. It is greatly appreciated.