No water coming out of the exhaust on muffs

[DuKn]

2000 Bayliner 1850 Capri 4.3l Mercruiser Alpha One Gen 2

Recently i’ve replaced the water pump on the lower unit and took the upper unit off to check bellows and u joints, i’ve also replaced the thermostat (the boat has only been in fresh water) got everything back on now and let it run for a minute on muffs and noticed there was no water coming out from the exhaust so i shut it off, i drained out all of the water from the system and started it back up, only the exhaust manifolds filled back up with water. I thought the thermostat had a bypass that allowed water to still come through the system?

 

[ESGWheel]

The thermostat does not need to come open or be bypassed for water to enter into the Exh Manifolds and out the exhaust. See this post (link) that has a water flow diagram. The t-stat controls the circulation of the water in the block > closed to allow it to warm up and cycles open / shut to control temp. Think of this way: the exhaust manifolds would burn up if only time getting water was thru the t-start (bypass or otherwise).

So, something is wrong and good you shut it down. I am not familiar with the Alpha drives and their internal seawater pump and hoses but something wrong. This assumes in the past you have gotten good flow out of your hose and muffs.

 

[DuKn]

did a little more playing, all the core plugs have water in them after draining and starting it back up, although the left side has like a suction to it, it’s not a straight draining like the right side does. The boat has begone smoking (white smoke) after starting up, and sounds kinda rough, i’m going to wait for some reply’s so i don’t hydro lock anything.
Yes, I was getting good flow before i did all of this. Water came out of exhaust fine and no water smoke and that was a few weeks ago, no freezing temps between then and now.

 

[Stinnett21]

When you changed the impeller did you get the key back on the driveshaft? The hose will force water up to some extent but without the impeller turning it won't be enough.

 

[DuKn]

I did put the key back, i remember putting a little grease behind it to keep it from falling out

 

[Scott06]

I did put the key back, i remember putting a little grease behind it to keep it from falling out

Were pieces of the old impeller missing ? If so they can clog the cooling system

 

[DuKn]

Were pieces of the old impeller missing ? If so they can clog the cooling system

No, it looked brand new

 

[ratdude747]

What kind of muffs do you have? On my mercruiser (1976 888/mc-1) I ended up having to use the bravo-style mercruiser muffs (looks like a set of crash cymbals). I had no luck with an "earmuffs" style muff set and bbq'd a new impeller partially as a result of such. You will have to drill a hole in the intake plates to use said mercruiser muffs (for the retainer rod/wire, see manual).

 

[DuKn]

Everything ran fine on my muffs before hand.

 

[jimmbo]

 

[Scott06]

No, it looked brand new

unless you mis fit the water tube coming up (which I think would direct the water to the prop exhaust which is not what yo are seeing), trace out the system.

Are you getting any water out the idle relief ports on the transom?

On the side of the thermostat housing the hose coming up from the drive - take that off you should be getting 3-4 qts in 15 seconds there (merc puts a spec in the manual).

do you have two or 4 smaller (1") hoses coming off the thermostat to the exhaust side. If four you have a separate feed to the elbows that should have a constant flow until the thermostat opens up. Usually there are check balls feeding this style that can hang up.

if you just have two lines going to bottom of manifolds they should have constant flow up through manifolds out elbows. You may have to remove some hoses to make sure flow is happening.

 

[DuKn]

I’ve got a trickle of water coming out on the relief port (only on the port side) that’s with the engine started and muffs on (didn’t run it longer than 30 seconds) and all of the core plugs have water still even after draining them and then starting back up to see if they would fill back up.
I have to same 4 tubes as shown in the diagram.

 

[Bondo]

I’ve got a trickle of water coming out on the relief port (only on the port side) that’s with the engine started and muffs on (didn’t run it longer than 30 seconds) and all of the core plugs have water still even after draining them and then starting back up to see if they would fill back up.
I have to same 4 tubes as shown in the diagram.

Ayuh,..... That's not long enough to fill the system, so that the exhaust can expel the used water,....

 

[DuKn]

unless you mis fit the water tube coming up (which I think would direct the water to the prop exhaust which is not what yo are seeing), trace out the system.

Are you getting any water out the idle relief ports on the transom?

On the side of the thermostat housing the hose coming up from the drive - take that off you should be getting 3-4 qts in 15 seconds there (merc puts a spec in the manual).

do you have two or 4 smaller (1") hoses coming off the thermostat to the exhaust side. If four you have a separate feed to the elbows that should have a constant flow until the thermostat opens up. Usually there are check balls feeding this style that can hang up.

if you just have two lines going to bottom of manifolds they should have constant flow up through manifolds out elbows. You may have to remove some hoses to make sure flow is happening.

I took the line off that goes from the drive to the thermostat and yes it’s getting plenty of flow.

 

[DuKn]

Ayuh,..... That's not long enough to fill the system, so that the exhaust can expel the used water,....

How long should i run it then? Longest I ran it was a minute, after i seen no water i shut it off really quick.
Before all this happened i was getting water immediately after starting the boat i think my thermostat was stuck open therefore i replaced it.

 

[Bondo]

How long should i run it then? Longest I ran it was a minute, after i seen no water i shut it off really quick.
Before all this happened i was getting water immediately after starting the boat i think my thermostat was stuck open therefore i replaced it.

Ayuh,.... It depends on how well it was drained,......
At spring start up, with my completely drained system, I wouldn't be concerned at the 2 minute mark,......
I've never timed it,...
It takes abit to fill a drained block,....

 

[DuKn]

Ayuh,.... It depends on how well it was drained,......
At spring start up, with my completely drained system, I wouldn't be concerned at the 2 minute mark,......
I've never timed it,...
It takes abit to fill a drained block,....

Right on the money Bondo, let it run for a few minutes then water started coming out. Guess I was too chicken to run it longer than a minute (for good reason) and me draining the block over and over would make sense of why it would take so long to come out just didn’t wanna burn anything up. Thanks for the help guys and gals.

 

[Stinnett21]

The kind of ending we like!

 

[Scott06]

Ayuh,..... That's not long enough to fill the system, so that the exhaust can expel the used water,....

x2 on this it takes long enough to just make you worry about water not coming out... 2 min is about right

Right on the money Bondo, let it run for a few minutes then water started coming out. Guess I was too chicken to run it longer than a minute (for good reason) and me draining the block over and over would make sense of why it would take so long to come out just didn’t wanna burn anything up. Thanks for the help guys and gals.

great problem solved, but you are right to stay on top of it. Watch water flow and oil pressure... never had an engine with both have an issue

And it is normal that you have uneven flow out the idle relief ports unless the trailer is dead level.

 

[Buster53]

Take out the T-stat and see what happens.