Troubleshooting order- water in one cylinder
09-12-2023, 06:40 AM
#1
Registered
Thread Starter
Troubleshooting order- water in one cylinder
My sons 24' Splendor 240 with Merc 305 MPI was running poorly. I had him change plugs and he found some water in 1 cylinder. He said it ran out when plug removed, hard to say how much water was there without knowing if that hole was close to TDC. No milkshake. He has rolled it over and lubed it up. Since he had not hydrolock condition I suspect that whatever was leaking was a mist causing it to run poorly and after it sat after the weekend run it slowly dripped into the cylinder.
History- 2004 model boat was bought after sitting last 4 years. I believe it lived all its prior life in FL likely on a covered lift. When T-stat was replaced a lot of rust in there.
Where water in exhaust can come from-
Exhaust manifold rotted.
Intake manifold gasket failed
Head gasket failed
Compression test, I think that would rule out the head gasket but not the intake gasket. I sort of thought rotten exhaust would water up several cylinders. Is there any history of the intakes on the SBC MPI having intake manifold sealing grief? If the compression test fails time to pull engine or attempt a head replacement in the boat. Engine is pretty buried and access is very difficult. Would need to inspect the deck condition as well. Would need to inspect manifolds as well.
If the test fails (have not done comp test yet)
Is it possible that a rotten manifold allowed it to injest enough water to blow the head gasket?
Flow test the injectors, could a sticky injector cause a lean condition and then blow head gasket?
Next step if compression test is good-
Remove engine or attempt in place intake and then head.
Is it common to have only 1 cyl to water up with bad exhaust or this more likely a head gasket or intake? There was no milkshake so that is a good sign so far. We will know more when comp test is done next weekend. Just looking for ideas on what to check first.
History- 2004 model boat was bought after sitting last 4 years. I believe it lived all its prior life in FL likely on a covered lift. When T-stat was replaced a lot of rust in there.
Where water in exhaust can come from-
Exhaust manifold rotted.
Intake manifold gasket failed
Head gasket failed
Compression test, I think that would rule out the head gasket but not the intake gasket. I sort of thought rotten exhaust would water up several cylinders. Is there any history of the intakes on the SBC MPI having intake manifold sealing grief? If the compression test fails time to pull engine or attempt a head replacement in the boat. Engine is pretty buried and access is very difficult. Would need to inspect the deck condition as well. Would need to inspect manifolds as well.
If the test fails (have not done comp test yet)
Is it possible that a rotten manifold allowed it to injest enough water to blow the head gasket?
Flow test the injectors, could a sticky injector cause a lean condition and then blow head gasket?
Next step if compression test is good-
Remove engine or attempt in place intake and then head.
Is it common to have only 1 cyl to water up with bad exhaust or this more likely a head gasket or intake? There was no milkshake so that is a good sign so far. We will know more when comp test is done next weekend. Just looking for ideas on what to check first.
Charter Member
09-12-2023, 07:13 PM
#5
Registered
Intake gaskets usually dont get water in the cylinder without also getting some in the oil but if it is a 2004 it probably has Vortec heads with the lousy early plastic intake gaskets so you never know. Ask him how many bolts hold the intake to the heads. If there is only 4 on each head it is a Vortec engine.
20 year old manifolds are definitely suspect too. Whatever he does tell him to get a mess of WD40 or something similar in that cylinder through the plug hole. ATF or even some diesel fuel works good too. The water will mess up the bore quicker than you would ever imagine.
20 year old manifolds are definitely suspect too. Whatever he does tell him to get a mess of WD40 or something similar in that cylinder through the plug hole. ATF or even some diesel fuel works good too. The water will mess up the bore quicker than you would ever imagine.
The following users liked this post:
j272 (09-13-2023)
09-13-2023, 04:48 AM
#7
Registered
My sons 24' Splendor 240 with Merc 305 MPI was running poorly. I had him change plugs and he found some water in 1 cylinder. He said it ran out when plug removed, hard to say how much water was there without knowing if that hole was close to TDC. No milkshake. He has rolled it over and lubed it up. Since he had not hydrolock condition I suspect that whatever was leaking was a mist causing it to run poorly and after it sat after the weekend run it slowly dripped into the cylinder.
History- 2004 model boat was bought after sitting last 4 years. I believe it lived all its prior life in FL likely on a covered lift. When T-stat was replaced a lot of rust in there.
Where water in exhaust can come from-
Exhaust manifold rotted.
Intake manifold gasket failed
Head gasket failed
Compression test, I think that would rule out the head gasket but not the intake gasket. I sort of thought rotten exhaust would water up several cylinders. Is there any history of the intakes on the SBC MPI having intake manifold sealing grief? If the compression test fails time to pull engine or attempt a head replacement in the boat. Engine is pretty buried and access is very difficult. Would need to inspect the deck condition as well. Would need to inspect manifolds as well.
If the test fails (have not done comp test yet)
Is it possible that a rotten manifold allowed it to injest enough water to blow the head gasket?
Flow test the injectors, could a sticky injector cause a lean condition and then blow head gasket?
Next step if compression test is good-
Remove engine or attempt in place intake and then head.
Is it common to have only 1 cyl to water up with bad exhaust or this more likely a head gasket or intake? There was no milkshake so that is a good sign so far. We will know more when comp test is done next weekend. Just looking for ideas on what to check first.
History- 2004 model boat was bought after sitting last 4 years. I believe it lived all its prior life in FL likely on a covered lift. When T-stat was replaced a lot of rust in there.
Where water in exhaust can come from-
Exhaust manifold rotted.
Intake manifold gasket failed
Head gasket failed
Compression test, I think that would rule out the head gasket but not the intake gasket. I sort of thought rotten exhaust would water up several cylinders. Is there any history of the intakes on the SBC MPI having intake manifold sealing grief? If the compression test fails time to pull engine or attempt a head replacement in the boat. Engine is pretty buried and access is very difficult. Would need to inspect the deck condition as well. Would need to inspect manifolds as well.
If the test fails (have not done comp test yet)
Is it possible that a rotten manifold allowed it to injest enough water to blow the head gasket?
Flow test the injectors, could a sticky injector cause a lean condition and then blow head gasket?
Next step if compression test is good-
Remove engine or attempt in place intake and then head.
Is it common to have only 1 cyl to water up with bad exhaust or this more likely a head gasket or intake? There was no milkshake so that is a good sign so far. We will know more when comp test is done next weekend. Just looking for ideas on what to check first.
09-13-2023, 02:28 PM
#8
Registered
Thread Starter
Salty, lived most it's life in FL on the bay. It is now in KY.
I ran a quick compression test today. #1 was 180 after 4 full cranks. Adjacent cyl #3 was 170. It occurred to me that he WD'd #1 so i put a shot of WD in #3 and rolled it over a few time and rechecked. Got close to 180, maybe 177 but battery was a smidge lower. I wonder what a 04 305 should check at? I think my gauge is a bit off but it was the balance that I was looking for. We will pull manifolds this weekend.
This is also a wakeup call to address any other issues a salty has. My boats have all been freshwater so have not had to deal with salty grief. I did boots and bellows for him past spring as I was addressing a bad case of bravoitis. It was corroded mostly closed. Would run hot on the hose but we have that sorted out. I think it also a good idea to flow check the injectors as it sat for a few years once it left FL and I do not know its maintenance history. MPI is new to me, I always ran Q-Jets or Holly with a blower under it. Much easier!
I am aware of the grief risers can cause but I would have though several cyl would be wet? Maybe not, just need to pull and inspect very carefully, perhaps rug up a jig to pressure test or look for a new set in good shape. They gotta be a little crispy.
I ran a quick compression test today. #1 was 180 after 4 full cranks. Adjacent cyl #3 was 170. It occurred to me that he WD'd #1 so i put a shot of WD in #3 and rolled it over a few time and rechecked. Got close to 180, maybe 177 but battery was a smidge lower. I wonder what a 04 305 should check at? I think my gauge is a bit off but it was the balance that I was looking for. We will pull manifolds this weekend.
This is also a wakeup call to address any other issues a salty has. My boats have all been freshwater so have not had to deal with salty grief. I did boots and bellows for him past spring as I was addressing a bad case of bravoitis. It was corroded mostly closed. Would run hot on the hose but we have that sorted out. I think it also a good idea to flow check the injectors as it sat for a few years once it left FL and I do not know its maintenance history. MPI is new to me, I always ran Q-Jets or Holly with a blower under it. Much easier!
I am aware of the grief risers can cause but I would have though several cyl would be wet? Maybe not, just need to pull and inspect very carefully, perhaps rug up a jig to pressure test or look for a new set in good shape. They gotta be a little crispy.
Last edited by BadDog; 09-13-2023 at 02:31 PM.
09-13-2023, 03:33 PM
#10
Platinum Member
Platinum Member
iTrader: (6)
If it doesn't have closed cooling and wasn't flushed properly its probably eaten up inside, Ive seen it first hand on a pair of 500 EFI's
The following users liked this post:
sutphen 30 (09-13-2023)
