Water getting in block from manifold/muffler-need help

[Fishin4Diamonds]

I have been having issues with the new to me boat. It is a 1999 Stamas with mercruiser 350's. I have replaced both engines, manifolds, risers. I have now blown the head on each engine already. I am getting just a slight amount of water in the head after the boat sits for a week or two after a use then I go to start it and ended up with a blown valve. It appears the seals on the manifolds and risers are solid so now I am trying to figure out why water is still getting in. Any help or suggestions? I sure don't want to keep replacing heads on the engines.

 

[Bondo]

Re: Water getting in block from manifold/muffler-need help

I have been having issues with the new to me boat. It is a 1999 Stamas with mercruiser 350's. I have replaced both engines, manifolds, risers. I have now blown the head on each engine already. I am getting just a slight amount of water in the head after the boat sits for a week or two after a use then I go to start it and ended up with a blown valve. It appears the seals on the manifolds and risers are solid so now I am trying to figure out why water is still getting in. Any help or suggestions? I sure don't want to keep replacing heads on the engines.

Ayuh,.... Welcome Aboard,.... Is this week sittin' in the water, or on the wagon,..??

What was found to be the actual Problem when ya lost the motors before,..??
Was it really Diagnosed, or just swap the motors,..??

How L o w in the stern, does yer boat sit,..??

Who's doin' the work/ diagnosin',..??

 

[Bt Doctur]

Re: Water getting in block from manifold/muffler-need help

cracked blocks, cracked heads, warped heads, improper head installation, new manifolds leaking internally

 

[Fishermark]

Re: Water getting in block from manifold/muffler-need help

Welcome aboard!

I have been having issues with the new to me boat. ....I am getting just a slight amount of water in the head after the boat sits for a week or two .

I assume it is sitting in the water. In addition to the suggestions above, it is a good idea to find out the level of the water in relation to your risers. Here's a pic to show how to do it:

 

[Fishin4Diamonds]

Re: Water getting in block from manifold/muffler-need help

The boat does stay in the water. Originally the engines had very bad compression in the engines when I bought it which is why the motors were replaced. Almost everything was redone including all pumps, intakes, manifolds, risers, etc. I don't think anyone has come up with the "why" it is still failing and getting water. I was told to drain the risers/manifolds after use. This does not seem like a solution to the problem. I was also told by some others that my muffler is almost even with the riser and may be getting water back through the manifold into the head causing it to rust while not in use and then failing when I start it several weeks later. They said to drill holes through the baffles in the muffler to help water drain. Someone else said that the run is so short from the exhaust that as the engine cools it is creating a vacuum and causing the water problem. They said to install a vent tube in the muffler.
The boat does not sit low in the water. It only draws 2 feet. The risers are right at the top of the engine and they could not be any higher due to the engine hatch.
I have not used the boat after getting the port engine head redone. I can't afford to go out fishing 40 miles and the next time I try and go out I blow another head.
The boat runs flawless when I do use it. All the water issues happen after a trip, the boat sits for a couple weeks, then fails when I start it up. This has happened twice now (once on each engine) and I don't want to use it until this water issue is figured out.

 

[Bt Doctur]

Re: Water getting in block from manifold/muffler-need help

Do Fishermark`s test . Sounds like your engine is below the hatch . Need to know if you are using manifold extentions between the manifold and riser..
E must be 13 inches or more

 

[Walt T]

Re: Water getting in block from manifold/muffler-need help

That is called the static water line. You may need to raise riser height. 13 inches is minimum, if you're right at 13 then I suggest raising it anyway. I have seen boats that actually were waterlogged in the transom and floors, and had water under floors, which added a lot of weight causing them to sit lower in the water. It doesn't take much. If you find your static line is less than 13 you need to find out why. It's logical to assume it didn't always have that problem. Sometimes adding extra batteries or gear or storing a genset back there does it.

 

[Bondo]

Re: Water getting in block from manifold/muffler-need help

The boat does stay in the water. Originally the engines had very bad compression in the engines when I bought it which is why the motors were replaced. Almost everything was redone including all pumps, intakes, manifolds, risers, etc. I don't think anyone has come up with the "why" it is still failing and getting water. I was told to drain the risers/manifolds after use. This does not seem like a solution to the problem. I was also told by some others that my muffler is almost even with the riser and may be getting water back through the manifold into the head causing it to rust while not in use and then failing when I start it several weeks later. They said to drill holes through the baffles in the muffler to help water drain. Someone else said that the run is so short from the exhaust that as the engine cools it is creating a vacuum and causing the water problem. They said to install a vent tube in the muffler.
The boat does not sit low in the water. It only draws 2 feet. The risers are right at the top of the engine and they could not be any higher due to the engine hatch.
I have not used the boat after getting the port engine head redone. I can't afford to go out fishing 40 miles and the next time I try and go out I blow another head.
The boat runs flawless when I do use it. All the water issues happen after a trip, the boat sits for a couple weeks, then fails when I start it up. This has happened twice now (once on each engine) and I don't want to use it until this water issue is figured out.

Ayuh,.... Post some pictures of yer exhaust system, 'n do the static water line test posted by Mark,....

 

[Fishin4Diamonds]

Re: Water getting in block from manifold/muffler-need help

Ayuh,.... Post some pictures of yer exhaust system, 'n do the static water line test posted by Mark,....

Thanks all. I will check the waterline and post some pics this weekend. Not sure what I would do if the line is less than 13 inches as the risers are about as high as they could go in the hatch. We will see.

 

[Scott Danforth]

Re: Water getting in block from manifold/muffler-need help

if you are below 13", you have to raise the risers. if the hatch and floor are in the way, you have to raise that too.

the 13" is a minimum and not a suggestion. it is there to keep your motor from sucking water.

or as many have mentioned, find out what has squatted the back of your boat farther into the water and fix that.

 

[Fishin4Diamonds]

Re: Water getting in block from manifold/muffler-need help



Update from waterline test. Results from test were 14 1/2 inches from waterline to the top of the riser. Please note that i do only have about half the fuel capacity on the boat. the tanks are in the back and normal waterline upon full tanks will be an inch less putting the riser at 13 1/2 inches above the water. i have attached some pictures of the setup. So if it is not a riser "height" issue what other suggestions/experience does anyone have. Someone this weekend said something about condensation. Could that really be a problem? dont all engines have some amount of condensation? Any other help is appreciated.

 

[Bondo]

Re: Water getting in block from manifold/muffler-need help

Ayuh,.... At 13, 1/2"s, with only 1/2 a load of fuel, 'n no passengers,....

Yer gonna need to seriously lighten yer ship, or figure a way to add atleast a 3" riser block,...

'n, no, it ain't condensation,...

 

[Scott Danforth]

Re: Water getting in block from manifold/muffler-need help

or stay on plane

 

[Walt T]

Re: Water getting in block from manifold/muffler-need help

Yup. I once had a guy asking me about the static water line. Said he was measuring it at 17 inches. After lots of back and forth e mails and texting he mentions the boat is on the trailer and he's measuring it all from the waterline on the hull. I couldn't make this stuff up.