Hydrolocked my motor
12-19-2011 | 01:53 AM
#11
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Joined: Oct 2000
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From: Omaha/LOTO
You said the engine hydrolocked, but then you say that you pulled all the plugs and there was no water in the cylinders. It sounds like you could have multiple issues. The Merc Gils were very susceptible to reversion, especially in the earlier years before they changed the risers.
If you've got 80psi and are not seeing any leaks, then the manifolds are fine. They only see about 3psi at idle.
It is a dry joint. Water passes between via a hose.
If you've got 80psi and are not seeing any leaks, then the manifolds are fine. They only see about 3psi at idle.
I'd bet the riser/elbow went bad. What did the manifold/riser gasket look like?
If not those, then the only other answer is reversion. You could have hit some harmonic holding it at 1500 that sucked water down, but the exhaust pressure kept it from entering the exhaust valve. Once you dropped back to idle, there would have been much less exhaust gas velocity coming out of the cylinder, with the exh valve staying open longer, allowing it to flood.
If not those, then the only other answer is reversion. You could have hit some harmonic holding it at 1500 that sucked water down, but the exhaust pressure kept it from entering the exhaust valve. Once you dropped back to idle, there would have been much less exhaust gas velocity coming out of the cylinder, with the exh valve staying open longer, allowing it to flood.
12-19-2011 | 07:12 AM
#13
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Joined: Aug 2005
Posts: 263
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From: Gothenburg, Sweden
You said the engine hydrolocked, but then you say that you pulled all the plugs and there was no water in the cylinders. It sounds like you could have multiple issues. The Merc Gils were very susceptible to reversion, especially in the earlier years before they changed the risers.
If you've got 80psi and are not seeing any leaks, then the manifolds are fine. They only see about 3psi at idle.
It is a dry joint. Water passes between via a hose.
If you've got 80psi and are not seeing any leaks, then the manifolds are fine. They only see about 3psi at idle.
It is a dry joint. Water passes between via a hose.
Agree with Griff, odd that you did not find any water in the cylinders.
12-19-2011 | 07:53 AM
#14
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Joined: Jun 2005
Posts: 8,407
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From: Central IL
Merc had a bulliten out awhile back on running their motors on a garden hose. They recommended @ 1,200 RPM and not to have a ton of water pressure coming out of the hose. When you backed off the lower RPM and high water pressure could have reverted water. Are you sure it didn't just drop a couple of cylinders and die?
12-19-2011 | 05:05 PM
#16
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Joined: Mar 2010
Posts: 156
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From: So Cal
You said the engine hydrolocked, but then you say that you pulled all the plugs and there was no water in the cylinders. It sounds like you could have multiple issues. The Merc Gils were very susceptible to reversion, especially in the earlier years before they changed the risers.
If you've got 80psi and are not seeing any leaks, then the manifolds are fine. They only see about 3psi at idle.
It is a dry joint. Water passes between via a hose.
If you've got 80psi and are not seeing any leaks, then the manifolds are fine. They only see about 3psi at idle.
It is a dry joint. Water passes between via a hose.
12-19-2011 | 05:11 PM
#17
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From: So Cal
I'm just gonna tuck my tail between my legs and pull the motor out, and tear it down. I'd rather it be right then questionable, besides I got all winter.
12-19-2011 | 07:15 PM
#19
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From: IBX
Horrible feeling. I broke a crank near WOT right after labor day so I can associate well. Good luck and hopefully it won't be too bad in there because it was not under heavy load/rpm. Let us know what you find.
Last edited by blue thunder; 12-19-2011 at 07:19 PM.
12-19-2011 | 09:28 PM
#20
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From: So Cal
Thought about that.. But doesn't make sense at idle.. cold water on the stem maybe. I was pretty careful when I built this thing. I put 11/32 stem valves in it and clearanced the exhaust stems to .0018-.0020. There would have to be a lot of movement to stick them.
When I get it apart I'll post up some pics so all you guy's can have some fun at my expense
I'm trying to have a sense of humor....
When I get it apart I'll post up some pics so all you guy's can have some fun at my expense
I'm trying to have a sense of humor....
