Hydrolock Water Intrusion...

[RonnieQ]

I have been reading all the threads about water leaks, hydrolocks, etc... I have a 2001 Four Winns 5.7GS and have encountered the dreaded hydrolock in the middle of the lake. So far, I have removed the Risers, ordered new Riser gaskets, extracted 2 broken starter bolts (don't want to do that again)... and done alot of investigating and testing, but still have not proved where the water came from... The risers and exhaust manifold look ok to me, there is no water in the oil, had alot of water in #8 and #5, but some in most all cylinders, both sides of motor. I have been told too many different things now to decide what to do... Working on now dis-proving the blown headgasket theory... Have been told that the "dieseling" theory shouldn't have caused it... which it did "diesel" on me that day at the lake or the day before... I never put 2 and 2 together at the time.... I am going to run a compression test today and also a leak-down test maybe on the cylinders to try and test the blown head gasket theory... then I guess maybe put it all back together and test it out in driveway to see if water still enters the system... what do you experts think? Is it really, really, possible for the "dieseling" to cause water to suck back thru the exhaust? Thanks !!!!!!

 

[Haut Medoc]

Re: Hydrolock Water Intrusion...

I have been reading all the threads about water leaks, hydrolocks, etc... I have a 2001 Four Winns 5.7GS and have encountered the dreaded hydrolock in the middle of the lake. So far, I have removed the Risers, ordered new Riser gaskets, extracted 2 broken starter bolts (don't want to do that again)... and done alot of investigating and testing, but still have not proved where the water came from... The risers and exhaust manifold look ok to me, there is no water in the oil, had alot of water in #8 and #5, but some in most all cylinders, both sides of motor. I have been told too many different things now to decide what to do... Working on now dis-proving the blown headgasket theory... Have been told that the "dieseling" theory shouldn't have caused it... which it did "diesel" on me that day at the lake or the day before... I never put 2 and 2 together at the time.... I am going to run a compression test today and also a leak-down test maybe on the cylinders to try and test the blown head gasket theory... then I guess maybe put it all back together and test it out in driveway to see if water still enters the system... what do you experts think? Is it really, really, possible for the "dieseling" to cause water to suck back thru the exhaust? Thanks !!!!!!

Absoloutely......

 

[Deanrw3]

Re: Hydrolock Water Intrusion...

Does your motor have exhaust flappers? Just a thought that I didn't see you mention.

Sorry to cut it but,

Can someone explain what "dieseling" is. I keep reading it on the board and can't figure out what everyone is talking about.


Thanks,
Dean

/hijack

 

[Maclin]

Re: Hydrolock Water Intrusion...

"Dieseling", also known as "run on" .....The engine runs on after the ignition is turned off. Common causes in a boat engine are too high of an idle, wrong heat range spark plugs, timing advanced too far, engine too hot.

If a boat engine is a chronic "dieseler" then it is a good idea to let the engine idle for a bit before it is turned off, this helps it cool down some, also run the blower as it idles. Sometimes a higher octane fuel is the answer if all other causes have been addressed.


Remember the carbed smog cars from the late 70's and early 80's, many had this problem. They would run on for minutes at times then finally rev up and shudder then die.

 

[RonnieQ]

Re: Hydrolock Water Intrusion...

I understand the concept, but still can someone explain how the RunningOn can suck enough water back into the motor enough to fill up a cylinder. A mechanic from here locally didn't think possible. I am wanting to lean towards that explanation, because everything else I check out seems to be ok... and it would be cheap fix.... I have new Riser gaskets and can put everything back together easily. If head gasket etc... then someone else will have to tackle that.... $$$$$
btw, my 2001 FourWinns 5.7gs does not have flappers...
Thanks all .....

 

[danond]

Re: Hydrolock Water Intrusion...

If your boat is dieseling, get it tuned up before you spend a bunch more money chasing the problem. It shouldn't do that.

Very few things are impossible when it comes to water ingestion. Your mechanic must be pretty new at this, or is trying to lighten your wallet.

 

[Maclin]

Re: Hydrolock Water Intrusion...

The exhaust pulses during dieseling are way too weak and also too irregular to keep the water in the riser coaxed into going on out the exhaust, but the water keeps getting pumped in anytime the engine is turning. As soon as the engine dies any water that did not get blown solidly out the exhaust runs from the inside of the riser down into the manifold.

It will not be a lot, more like tea/tablespoons instead of quarts, but if one cylinder gets the whole "shot" then it is enough to cause hydrolock or worse and bend a rod when cranked the next time. It is actually a blessing if the engine cannot turn over AND the operator figures it out and pulls the spark plugs to relieve the condition.

 

[Maclin]

Re: Hydrolock Water Intrusion...

And like danond points out, fix the issue that is causing the dieseling, well worth the effort and expense.

Try idling for a bit before shutting down if you are not now, that may help, and have the blower on to keep new air coming in as any extra cooling can help.

 

[RonnieQ]

Re: Hydrolock Water Intrusion...

Thanks !!!
I wasn't aware of a 'dieseling' problem until this one time. After 3 weekends on the lake with no problems... It did it once and then at some point we pulled into a cove to swim for a bit and then the dreaded hang-up.... sheared starter bolt... and hydrolock....
Not sure why the 'run-on' occurred unless bad gas, or because we were tugging along at low RPMs with a child on a tube... like really really slow... that's too why I am wandering if the water just came thru the exhaust while it was dieseling and I am chasing a mechanical failure that does not exist...
Thanks again for all the replys. I really would sleep good at night to find 100% what the cause was....

 

[RonnieQ]

Re: Hydrolock Water Intrusion...

So here is my plan for today:
I am going to run compression test on all cylinders and if all check out ok, then I am going to put everything back together along with the new Riser gaskets, get it started and runnings with water muffs, let it run for awhile till normal operating temperature is reached, shut it down, wait a bit, and then pull the plugs and check for water.... if ok, will repeat the process several times, and never anymore leakage, may call it good and head to the lake...
Sound like a good plan?
If test are bad, then back to the drawing board....

 

[Maclin]

Re: Hydrolock Water Intrusion...

I think that is what I would do after checking all the mating surfaces.

 

[RonnieQ]

Re: Hydrolock Water Intrusion...

So what do you think DonS?

 

[Don S]

Re: Hydrolock Water Intrusion...

When an engine diesels, it runs backwads, making the exhaust system the intake system during the dieseling. Since there is water in the exhaust, it gets into the exhaust manifold and the cylinders with open exhaust valves.

 

[RonnieQ]

Re: Hydrolock Water Intrusion...

Sorry to beat a dead horse... but my uncle, master mechanic for 40+ years said a gasoline engine would not run backwards.... With all the symptoms though..... it ran fine, never overheated, gave no warning signs etc... just that one time that it "Ran-On" and then later we pulled over into cove and shut it off... then went to start it up and bang... it was locked... Nothing I have checked so far shows any leaks, head blown or anything... so I think that must have been the problem and hope that was the problem... even though I can't convince a few people from around here... him and the boat mech locally.... so guess I will put it all back good and sound and test it out thoroughly.... Thanks

 

[Don S]

Re: Hydrolock Water Intrusion...

but my uncle, master mechanic for 40+ years said a gasoline engine would not run backwards....

He's right. they won't run backwards, but they will diesel/runon backwards.

 

[RonnieQ]

Re: Hydrolock Water Intrusion...

Guess that is why they call it "Dieseling" because a Diesel engine can run backwards..(atleast that is what he also said)....
SO.... I am slapping it all back together and firing it up (with water) and see what we get....
Thanks !!!!! Let ya know !!!!!

 

[Don S]

Re: Hydrolock Water Intrusion...

Here is a Merc Service bulletin on the subject you can download

http://www.4shared.com/account/file/54408916/4cd96d00/01-13_Gas_Engines_and_Water_Intrusion.html

 

[RonnieQ]

Re: Hydrolock Water Intrusion...

Thank You !!!!

One last question before I go.... I am assuming if per chance there is a water leak somewhere (head gasket etc...)... that as long as the engine is running, it won't hydrolock on me?

I want to get it running and let it run for a while to get to operating temperature... then shut off, pull plugs and verify....

Thanks again !!

 

[John_S]

Re: Hydrolock Water Intrusion...

When the engine diesels, it is fireing off of hot spots spots in the cylinder head, piston, carbon, etc. The ignition can occur long before the piston reaches near top dead center, causing the engine to reverse direction. Many times when an engine diesels, it will initially be rotating in the correct direction, but just before it stops, it will reverse for a half, full, or sometimes more rotations. The reverse rotation causes the exhaust to act like an intake, sucking in exhaust gas and water.

 

[Don S]

Re: Hydrolock Water Intrusion...

I am assuming if per chance there is a water leak somewhere (head gasket etc...)... that as long as the engine is running, it won't hydrolock on me?

It could, if the leak was big enough to allow enough water in during a zero compession part of a stroke. But I doubt that is yor problem on a marine engine