Water in cylinders--Have a theory--Whats your thoughts?

[Moose]

So here's what happened. Boat was overheating on the lake so i shut it down to investigate. Plenty of water going into the engine probably a stuck thermostat. Went to restart and the engine made about one spin then wouldn't turn over at all. Was thinking the worst (seized) Got the boat loaded and started pulling spark plugs. Found water in every cylinder the rear downhill one's had the most. Got the boat home and started pulling parts. Intake manifold good. Intake Gaskets good. Exaust manifolds had water in the exaust ports. Pulled the heads both of them look great. Head gaskets look almost brand new. Block looks great no cracks visible anywhere. Piston tops look brand new. Engine only has about 100 hours since rebuild. Engine was winterized properly plus no visible signs of a freeze. No water in the oil. Every cylinder has great compression. So here go's my theory Either the gasket in the exaust manifold that seals the two sections right at the elbow burned out or my exaust flappers that look like their due to be replaced let water get sucked into the engine when i shut it down. I have heard of this happening to trucks when the exaust pipe is under water and the engine is shut off. The hot engine sucks the water up and into the cylinders. The amount of water i found in the cylinders would indicate either a catostrophic faliure which didn't happen or maybe my hot overheated engine sucked up water through a burned out exaust elbow gasket or straight up the pipe.

Has anyone had this issue with a thru hull exaust boat before? Anyone have any ideas or thoughts? I would like to hear them.

[docdrs]

Interesting situation. First tho , if the engine was getting lots of water why did it overheat?

[Moose]

I belive the thermostat got stuck closed in the housing. It was pretty crusty. But i'm not 100% on that.

[DKJBama92Mariah]

Exactly how bad are the flappers? Pics would be great.

Also, how hot was the overheat? Where was the temp gauge.

A hot engine won't just suck water up the exhausts into the manifolds and cylinders, but the flappers do serve a purpose. There are two main way water can be forced up the exhaust and into the cylinders. First, if while stopped you catch a big wave to the transom with the engine off, the wave can travel up the exhaust pipes into the center of the riser and down into the manifolds to the exhaust valves. Second, if the engine is shut off while the boat is up on plane without idling down first, the trailing wave that forms behind the boat will crash into the transom. Without flappers or engine exhaust to stop it, this wave will also travel up the exhaust pipes and into the manifolds. Flappers in good condition protect the engine in both of these scenarios.
'
Also if the manifold do get flooded, the engine doesn't immediately lock up because only a couple of exhaust valves are open at any one time. But once the water it in the manifold, it will sit in the runners until the exhaust valve opens. It would take one or two turns of the engine, just as you described, for all the valves to have opened and completely lock the engine up.

Does either of the two situations fit you? Flapper condition is critical here. We NEED to know how bad they are.

I would get some sort of oil into those cylinders pronto to keep the cylinder walls and rings from rusting. Also check the oil for water contamination. You will want to change it before running it again anyway.

I really don't think you burned though the riser gasket. It is made of some pretty resilient stuff. It seemed almost like lead when I scraped it off the last time I had my risers off. I'm pretty sure if you got it hot enough to burn through that gasket, it would cook the exhaust hoses on the manifolds. You'd know it if you did that, those hoses smoke and stink when they start to melt.

[DAFF]

I wonder if the engine dieseled a tad on shut down and made the engine turn in reverse sucking the water in the manifolds into the engine. I could see the cooling effect pulling water in too but there would beed to be a plug on the top of the carb for it to happen....

[jet]

?? man haven't heard of this one before?? I have heard (not sure if its true) that manifold gasket in the middle of the manifold keeps the water out so If It fails, water in the engine?? Keep us informed. New engine?? Man that hurts. Sorry man.

[Moose]

DKJ My flappers are intact but because of their age the flapper part sticks out at a 30 deg. angle so I belive on engine shut down they are staying open but they would still close on a wave situation. Dont know if the engine could suck the water that far but some of the exaust is under the water line so with flappers open it would fill them anyway. After stoping the engine when I went to restart it did make about 1 to 1 1/2 spins before it locked up. Later I found water in every cylinder the rear downhill ones had the most. Durining tear down I had some water spill out of the exaust manifold at the ports. That plus not finding any evidence of a failure leads me to the engine taking a drink sceniero. Haven't had a chance to pull apart the exaust risers yet. Right after this happened and i pulled the plugs and spun the engine over a couple times to squirt out the water then used a whole can of fogging oil in the intake, and spark plug holes while turning over a couple more times. The other day when I pulled the heads I didn't have any rust.

The oil looks good not milky and I can't see any signs of water but i will change and flush a couple times with fresh oil when I get it running. Exaust hoses didn't burn.

The engine taking on water through the exaust is the only thing I can come up with for what happened. Everything else looks great. I can find no signs of any other failure.

Thanks guys for your input I will keep ya updated on what I find and I will take some pics. of the flappers. Now I'm gonna go spend some money with skidim.

[docdrs]

Is this a salt water boat?

[Moose]

Nope fresh water.

[csuggs]

My first thought when I read the thread was your engine spun backwards. Not sure how this happens, but I've heard of it. And the flapper condition doesn't necessarily matter because even with the flappers closed, there's enough water in the exhaust manifolds and hoses to fill the cylinders.

[Moose]

I didn't notice the engine diesel or spin backwards but it is possible that I shut it down right on a compression stroke and it may have spun back enough to suck water in the cylinders that were on their exaust stroke. That would have filled the exaust manifold too so when i went to restart more cylinders would get a bath. I'm just glad it's something easy--no broken or cracked expensive parts.

[Salty87]

i can't tell you why but you're not alone. i've had to blow water out once before but i don't think it was all 8 cylinders. boat stalled and wouldn't restart. i never did figure out why and it hasn't happened again.

[sydneyACE]

I have some doubts about your engine "sucking" water-in through the exhaust. I'm assuming you have a 351. That's roughly 5.7l displacement every TWO revolutions. If it DID happend to manage to make 1 FULL revolution backwards, that's 2.85l for BOTH sides. Each side would be less than 1.5l.
Imagine how many 2 liter soda-bottles it would take to fill your entire exhaust system. Sure, after it sat for a while with a flapper stuck-open, it would fill the exhaust up to the water-line. (This is assuming water-pressure doesn't hold your flappers closed when your boat is in the water.)
I don't know... I just don't see-it. Unless there's somthing I'm missing, I think your engine would have to spin backwards at LEAST 2 revolutions (even with the exhaust half-full) to actually "suck" water in from the exhaust.

Is it possible your manifolds have cracked on the inside water jacket? Once the engine is off, the water stored in the walls of the manifolds could leak through those cracks and down into an open exhaust valve. I've heard of that happening before. I don't know about all cylinders though. That seems pretty odd to me. Any way, let us know what you find. Good-luck!

[DAFF]

Here's what I think what happened. You engine Tsat was stuck causing the engine to heat up. On shut down the engine was very hot and the engine loaded up with gasoline vapour. The heat from the engine caused the engine to re-fire not using a spark plug but rather the engery from the compressed gasses in the cylinder on the up stroke. This then in turn turnded the engine backwards and created the diesel effect. This caused the carb to become the exhaust and the exhaust the inytake making the engine gulp some fluid. The engine wold not diesel very long for the fact water is non compressable and thus a hydrolock was created. This is why the engine seemed siezed too.

I might be wrong but at least my theory make logicial sence. The good news is a new T stat and all will be good.

[86 century]

Daff is probly correct

At most it will have 100cc of combustion space it takes a very small amout of water to lock one up.

[Moose]

Here's a pic of my old flappers. Yeah they just like to stay open. These are my #1 suspect for water in the cylinders
9588

Here's the new. So much better.
9589

Got one head bolted and torqued gonna try and get the other done tonight but there is a chance of rain delay.
When I get the the risers apart I will put up some pics.

[jet]

I dont think the flappers are the source of the problem?? #1 Your pipes and mine sit below the water line, which means most likley engine running or not, they are 100% filled with water all the way up to the the upward elbow of the pipes going up and into the exhaust risers. The flappers arent water tight. Im sure they help keep water out but there job isnt to be water tight. #2 Im not 100% sure how the exhaust risers work, but there is that gasket between the top and bottom and I have heard thats what keeps the water out of the enging since the exhaust is above the engine. There has to be a stopping point to keep water from flowing down hill and into the engine. That would be the point where water could or couldnt get in. I also dont think that backing up in reverse with the flaps open, that water could still get in the engine. Im just doing some open thinking here, maybe others can pipe in on what exactly happens inside the risers?? Keep us posted on what you do find out. Jet

[sydneyACE]

I'm kinda with you jet... As I posted earlier...
I ran mine without anything on the ends of the exhaust last season. (No flappers, not Supper Traps, no mufflers, nothing)
There was some concern of water "splashing" all the way up to the top of the risers and hitting a hot exhaust valve or something.
However, I didn't have any problems. (I was careful not to stop too quickly and risk my wake slamming into the back of the boat.)

Jet, the water goes in the front of the manifolds and is separated from the exhaust-flow by a "water jacket" (double wall). It then goes out the top of the manifold where it connects with the riser. The riser is built the same way as the manifold where it has a water jacket that keeps the water from mixing with the exhaust flow intil about 3-4 inches from the end of the riser. The water and exhaust mix way down at the end of the riser where it is already flowing "downhill" at that point. The riser and manifold have a gasket to seal them where they connect. I've heard of that gasket going-out and leaking water down into the manifold which will pool and leak-into any open cylinders when the engine is NOT running. The same problem can occur if that water jacket is cracked/coroded.

However, I just don't know if THAT much water could get into EVERY cylinder through that method. Water would pretty-much HAVE to come in the intake side for that to happen. Even when the engine is just cranking, it still produces quite a bit of pressure when the piston forces exhaust-out. I feel it would have to spin backwards (several revolutions) to actually pull that much water into the cylinder.

I know a lot about how engines work, but this one is a mystery to me...

[docdrs]

I'm with Jet and the ACE on this.......riser gaskets or internal crack on riser and or manifold. Probably gasket as the heat toasted them and they probably were not done in the rebuild and it occurred on both sides. Then when you cranked it you just added more water to the situation. The big question is was it really overheating and if so why? What led you to believe it was overheating? The temp gauge? I know you think it was your tstat but that would not affect the exhaust manifold, it would actually cause cooler water thru the manifold. Which I suppose may have cause an internal cracking? LOL Just writing out loud here.

[Moose]

Well the weekend was very productive. I spent about 10 hours working on the boat on Saturday and about 4 on Sunday but the beast is alive. Have some pictures below of my rotted out exaust riser gaskets. Think my overheat might have finished them off. They are now my #1 suspect for water in the cylinders. But I'm not ruling out bad flappers plus a rouge wave or hot engine sucking up water. Could also be the engine dieseling backwards allthough I dont remember it doing that. I have repaired every issue I could find and now the beast lives again. Just need the lake test. Check out my boat running vid.
96449645


http://www.youtube.com/watch?v=nYuHwm6lXRo&feature=player_detailpage
Thanks guys for all your input on this. I'm very happy to be up and running again.

[jet]

Those look ok, they still look solid but a bit clogged up which is normal after that many years. How about the gasket inbetween? How did it look? How easy did they come off, bolts did you break any and did you buy new ones already?

[lively]

make sure you put the new gasket tabs forward (toward the front of engine) .... if you dont .. you might have the same thing happen

[Moose]

The gaskets or whats left of them are on the risers in the pictures. The center sealing section that seperates exaust from water was mostly gone. It was a mix of paper gasket and rust. In one of the pics you can see rust lines running down into the exaust manifold. It was definatly leaking. Risers came appart pretty easy. Newer looking bolts. Gaskets were some kind of paper. I have seen the cheap paperones on ebay but I used the graphite impregnated ones. They look like their made just like exaust manifold gaskets. Used a large flat file to knock down the high spots. If it leaks again I may get the sealing surfaces milled down to flush. Or have to buy new ones.

New gaskets are installed tabs foreward.

[docdrs]

keep us posted

[Yama1]

Moose,

I just had the same occurrence this weekend on my beast with 454. Mine definitely was running hot as the impeller was in a ton of pcs. When I shut the motor down, it would not crank at all, clunk clunk. I have the theory of water being sucked in somehow due to the high temps with no water. I cleaned the cylinders, ran, drained the oil and double checked plugs for water entry and ran for 20~30 minutes with no issues so far. Today I did notice that the top half of my internal flapper was melted off which could be part of the reason, but logically doesn't make sense. I still need to do the load test on the lake and see what happens. Flappers are a pain to replace from what I can see- Hardin performance tips with internal flapper.
Glad to hear you also didn't have any internal damage. My riser gaskets could also be the culprit, but I don't see any evidence of that yet to justify replacing yet.

[Moose]

I'm still not 100% on the reason mine did what it did but after head, intake, exaust, and riser gaskets new flappers, impeller, and a couple oil changes the boat runs great. Had it out memorial weekend and it never got over 160 and never got water in the cylinders. I really think the overheating engine and bad flappers could be the issue but my riser gaskets were toast also so who knows.

[Hematoma]

Little late to the party but, I have the factory Supertrapps and NO flappers. The sucking water back thru the exhaust seems like a stretch? Mine would suck water everytime I would think? I have had my motor run backwards at the launch ramp on cold start up. Atleast 2 revolutions and it just can't get enough suction thru 3" pipe to suck water uphill? Crazier things can happen though I geuss.

[middlegriff1]

New to here guys, just bought a Salt and had this happen to me last night which left me stranded. Sorry to bring up an old thread but did you ever figure out exactly what happened? I pulled the plugs and its drying out now.

[cadunkle]

Explain what happened. Hydrolocked with water in most/all cylinders and wet inside manifolds. Cracked or rusted through manifold and/or riser. Failed manifold to riser gasket. Too hot of a cam causing reversion at idle. If happened when coming off plane could be lack of or broken flappers on exhaust. Head gasket is a possibility too but would typically only be one or two cylinders, not all or not on both banks. Need more details, but those are the things to check.

[middlegriff1]

I was on plane and noticed a loss of power so I throttled down to 5mph and it stalled out. After looking it over I noticed the temp was almost pegged. Ended up being the impeller was shot. Replaced that and pulled the plugs and turned the motor over. Water came out of every cylinder. It's been air drying overnight.

[Cusefan78]

The impeller being bad would over heat the motor but that's not causing water into the cylinders. Maybe when it overheated it expanded the gaskets somewhere allowing water into the cylinders. I would check the riser and head gaskets water is getting into your engine somewhere.

[middlegriff1]

The oil is clean so I think that the head gasket is alright. When I pulled the thermostat housing there was no thermostat in it so a buddy of mine thinks that the pieces of impeller could have caused a riser to stick? I'm flushing the motor and have pieces of impeller coming out of everything.

[docdrs]

If the oil is fine, and you have water in the cylinders it is most likely your riser gaskets. I would get oil into your cylindes asap to prevent rust of pistons and rings. Then change your riser gaskets, impeller and flush the engine and check everything. If its ok , i would change the oil , install 160 tstat and retest. Get oil or storage spray into your cylinder heads immediately as yyou dont want rust on your valves rings or pistons

[middlegriff1]

Im at the same conclusion as you docdrs, Ive got all the plugs out but one. There's a steel drain plug in the back of one of the manifolds that of course corroded in there and ive rounded out the end to. Im going to go get a pipe wrench and grab it around the threads and see if we can't get it out. I already bought a brass replacement so I don't get that headache again.

[middlegriff1]

So after the impeller replacement, new plugs, water out of the cylinders and a flush the boat is running fine. The riser gaskets were ok, so I'm thinking when the motor got hot and shut down it dieseled and pulled water back into the motor. It also had one of the exhaust flaps sort of sucked back into the exhaust which I thought nothing of at the time.

[docdrs]

So after the impeller replacement, new plugs, water out of the cylinders and a flush the boat is running fine. The riser gaskets were ok, so I'm thinking when the motor got hot and shut down it dieseled and pulled water back into the motor. It also had one of the exhaust flaps sort of sucked back into the exhaust which I thought nothing of at the time.

How do you know gaskets are ok? did you do some sort of test????? I can see failure from overheating, and ok now , but they will fail again........as far as water being sucked up into the motor all the way from the exhaust flappers thru muffler , if you have, up the exhaust tube and over thru the riser i doubt it. but just me. If an engine runs back wards or diesels the exhaust still is going out, water will not enter the cylinders think about it. iI have run my boat at 45mph and shut it down with no probs....even if you are running backwards the exhaust will far out weigh the water pressure..... that being said , I am glad everything is ok , but let us know if it is still ok after you run it hot a few times please. Things may change once its under a hot load with higher impeller pressures. i like to be told i'm wrong :)

[Cusefan78]

I agree I can't see water being sucked backwards all that way. Even if the motor was off and the flaps where open and the boat was being dragged backwards I can't see it. If I were you I would check the gaskets. Water in the cylinders is not a good thing.

[middlegriff1]

Im taking the boat out today to test, Ill let you guys know of my findings.

[middlegriff1]

So after the water test and two oil changes it seems like the temp keeps creeping up when I take the boat up past 3500rpms. Any thoughts?

[Jetlink]

So after the water test and two oil changes it seems like the temp keeps creeping up when I take the boat up past 3500rpms. Any thoughts?

Have you checked the raw water pump? What about the transmission cooler for blockage? Do you have a strainer on the water pick up line? Did you cook the old impeller and if so, did you pull the thermostat and find as many of the pieces as you could? Do you have any blocked passages anywhere before the thermostat? Did you replace the gaskets on the risers and manifolds?

[docdrs]

What is it going to? If you bring it down to idle , then rev the engine in neutral does the temp cool right down?

[middlegriff1]

Have you checked the raw water pump? What about the transmission cooler for blockage? Do you have a strainer on the water pick up line? Did you cook the old impeller and if so, did you pull the thermostat and find as many of the pieces as you could? Do you have any blocked passages anywhere before the thermostat? Did you replace the gaskets on the risers and manifolds?

I checked the trans cooler for blockage and there was none. The impeller is new, already flushed all the hoses and motor from the previous impeller falling apart. Im going to pull everything and flush again tomorrow and see how that works.

[middlegriff1]

What is it going to? If you bring it down to idle , then rev the engine in neutral does the temp cool right down?

The temp will keep climbing all the way up, when under 3500rpms it'll stay at 160. Yes revving it in neutral brought the temp down.

[docdrs]

Check all pre impeller clamps, could be sucking air at higher rpms. You could try without a thermostat and if it does the same maybe the circulating pump is going. .02

[Cusefan78]

I think the circ pump has a wheepe hole. Water drips out when they go bad.

[CornRickey]

Get a infrared temp gun and verify the temp is actually rising. My bet though is there is still pieces in the system. I had this problem after my impeller died. Took mea couple looks to find pieces jammed in the grate on theddischarge side of the pump.

[middlegriff1]

Well after pulling all the hoses again again checking for debris, the hose leaving the raw water pump into the thermostat housing was full of old impeller pieces. Flushed that and all is good, ran it for close to an hour between 3800 and 4400 rpms with the temp not even touching 150. ... CornRickey was on the money. Thanks everyone else for the help as well!

[Outsick]

Yes I would have to agree make sure their are no pieces of the impeller blocking anything including the trans cooler. And a hot moter can suck water up as it cools happened to me.