95 Cobalt/454 Mercruiser

[big2bird]

Going to look at a boat today for a friend. He went to start it, and it turned a partial revolution without firing and stopped. I had him remove the plugs, and water came out all cylinders. I doubt he could bend a rod with the starter.
I told him to squirt a tad of ATF in all cylinders and spin it over. Out came goo and water in all cylinders. Some more than others. It only has a few hundered hours on the clock.
I told him to drain the oil to show me, and I would take a look see today.
I am no boat guy, but I doubt a head gasket would show water on both banks, so I suspect a heat exchanger leak.
Suggestions/ideas?

 

[TimAT]

Water manifolds can crack too - and water will run everywhere. And a starter will bend a rod. Been there. And you are correct- a head gasket won't fill both banks, and the odds are pretty long for both gaskets to give up at the same time.

 

[BBShark]

Cracked exhaust manifolds? Is it a freshwater or closed cooling (seawater) setup?

I had a 22 ft Cobalt. It was the best built boat I ever owned. Also had the 7.4 Merc.

 

[mrvette]

Cracked exhaust manifolds? Is it a freshwater or closed cooling (seawater) setup?

I had a 22 ft Cobalt. It was the best built boat I ever owned. Also had the 7.4 Merc.

ONLY V8 boat I have any experiences with is a buddy's Chapparal ~22' and 350/AFB SBC, with dual water manifolds....Mercruiser....from what I could see I can't imagine how in hell one exhaust manifold could flood both banks....

that's why I thinking something stupid on the intake mani side....

 

[010752]

It's common for the raw water cooled exhaust manifolds to just rot out pretty quickly, doesn't matter if the engine itself is fresh or raw water cooled. Salt water makes it happen a lot faster.
If in engine, it isn't good, you decide, largely depends how damaged by how long it's sat unused. Again salt water is a lot faster.
If engine is raw water cooled, all the block/heads cooling guts will be like the manifolds. If saltwater, usually the block is corroded enough to be trash.

You may be able to repair/replace exhaust riser gaskets/manifolds to prevent more water intrusion and get it running, but a lot of life is gone out of the engine, your call with comp/leakdown tests. Start by taking the risers off.

Here is a very basic primer, remotely possible (<1%) it's not the exhaust at all.

http://www.boatfix.com/merc/Bullet/01/01_13.pdf

 

[big2bird]

It's common for the raw water cooled exhaust manifolds to just rot out pretty quickly, doesn't matter if the engine itself is fresh or raw water cooled. Salt water makes it happen a lot faster.
If in engine, it isn't good, you decide, largely depends how damaged by how long it's sat unused. Again salt water is a lot faster.
If engine is raw water cooled, all the block/heads cooling guts will be like the manifolds. If saltwater, usually the block is corroded enough to be trash.

You may be able to repair/replace exhaust riser gaskets/manifolds to prevent more water intrusion and get it running, but a lot of life is gone out of the engine, your call with comp/leakdown tests. Start by taking the risers off.

Here is a very basic primer, remotely possible (<1%) it's not the exhaust at all.

http://www.boatfix.com/merc/Bullet/01/01_13.pdf

Noonie, that link nailed it. There was clear water, not coolant in all cylinders in small amounts, and the sump has 7qts oil + about 3-4 qts water. I will change the oil and follow that bulletin instructions tomarrow. J
BTW: It is a closed loop system, that has only ever run in fresh water. I did a coolant pressure test, and only found a weep at a manifold/brass/elbow.

 

[big2bird]

Does anyone know if the raw water pump/fuel pump drive is positive displacement style?

 

[010752]

It's common for the raw water cooled exhaust manifolds to just rot out pretty quickly, doesn't matter if the engine itself is fresh or raw water cooled. Salt water makes it happen a lot faster.
If in engine, it isn't good, you decide, largely depends how damaged by how long it's sat unused. Again salt water is a lot faster.
If engine is raw water cooled, all the block/heads cooling guts will be like the manifolds. If saltwater, usually the block is corroded enough to be trash.

You may be able to repair/replace exhaust riser gaskets/manifolds to prevent more water intrusion and get it running, but a lot of life is gone out of the engine, your call with comp/leakdown tests. Start by taking the risers off.

Here is a very basic primer, remotely possible (<1%) it's not the exhaust at all.

http://www.boatfix.com/merc/Bullet/01/01_13.pdf

Noonie, that link nailed it. There was clear water, not coolant in all cylinders in small amounts, and the sump has 7qts oil + about 3-4 qts water. I will change the oil and follow that bulletin instructions tomarrow. J
BTW: It is a closed loop system, that has only ever run in fresh water. I did a coolant pressure test, and only found a weep at a manifold/brass/elbow.

Be aware that there are 2 types of freshwater systems.
Half and full. Half uses raw water to cool the exhausts and full uses freshwater to (coolant) cool the exhausts.
With the half, you can still get raw water into the cylinders via the manifold setup and the fresh water part will test good (it can go thru the exhaust ports and valves).

 

[big2bird]

The manifolds are plumbed with the coolant/sealed system.
The raw water cools the oil cooler, then the power steer cooler, then the heat exchanger, then exits via the manifold risers. The exhaust goes thru flappers, into a deer horn collector, and exhausts thru the stern drive.It has the blocking type gaskets between the exhaust manifold and the risers.(Bravo)

 

[010752]

Does anyone know if the raw water pump/fuel pump drive is positive displacement style?

The drive is a cam on the water pump shaft, just like on a regular camshaft, but the follower of the pump runs in a gear lube bath. Has to be a special fuel pump for that raw water drive. Follower or lever of the pump is different than regular pumps.

If you meant the fuel pump, it's the same as automotive, spring loaded inside, so it's not a positive pump. It should also have a vent port that goes to the carb.

Here is some more info. Pay attention to the raw water supply issues. It's common for the thru transom fitting to restrict if the supply is thru the lower unit instead of the hull. It would overheat in a heartbeat.
http://www.boatfix.com/merc/Servmanl/16/16A6R2.PDF

 

[big2bird]

Drained the sump on the boat. 4 gallons of water, and 2 gallons of oil.
The water level went so high, it pushed oil up thru the intake manifold, and out the carb, coating the top of the intake slightly. All while sitting on a trailer over a 2 year period. WTF? I am perplexed.
Coolant still green, and pressure tested fine. It is raw water in the oil.:huh:

 

[mrvette]

Drained the sump on the boat. 4 gallons of water, and 2 gallons of oil.
The water level went so high, it pushed oil up thru the intake manifold, and out the carb, coating the top of the intake slightly. All while sitting on a trailer over a 2 year period. WTF? I am perplexed.
Coolant still green, and pressure tested fine. It is raw water in the oil.:huh:

You have a CAT ASS TROPHY on your hands....we need pix for the archives....

engine is junk and I doubt rebuildable.....YGTBFKM....

major shit ain't right....

doubt the bottom end after 2 years is going to last 15 minits under marine use....
NFW....

 

[turtlevette]

Drained the sump on the boat. 4 gallons of water, and 2 gallons of oil.
The water level went so high, it pushed oil up thru the intake manifold, and out the carb, coating the top of the intake slightly. All while sitting on a trailer over a 2 year period. WTF? I am perplexed.
Coolant still green, and pressure tested fine. It is raw water in the oil.:huh:

Rain water got in somehow? Clean it up and see if you can get it started.

 

[big2bird]

Drained the sump on the boat. 4 gallons of water, and 2 gallons of oil.
The water level went so high, it pushed oil up thru the intake manifold, and out the carb, coating the top of the intake slightly. All while sitting on a trailer over a 2 year period. WTF? I am perplexed.
Coolant still green, and pressure tested fine. It is raw water in the oil.:huh:

Rain water got in somehow? Clean it up and see if you can get it started.

That's the plan. The water is crystal clear, with no signs of rust. Flush the oil system, start it up, and see what happens. What's done is done.
Not my boat, or a crate engine would be on the truck by now.:clap:

 

[010752]

Going to look at a boat today for a friend. He went to start it, and it turned a partial revolution without firing and stopped. I had him remove the plugs, and water came out all cylinders. I doubt he could bend a rod with the starter.
I told him to squirt a tad of ATF in all cylinders and spin it over. Out came goo and water in all cylinders. Some more than others. It only has a few hundered hours on the clock.
I told him to drain the oil to show me, and I would take a look see today.
I am no boat guy, but I doubt a head gasket would show water on both banks, so I suspect a heat exchanger leak.
Suggestions/ideas?

If he did that with all that water in the pan then the oil pump pumped water into the bearings too.

 

[010752]

Drained the sump on the boat. 4 gallons of water, and 2 gallons of oil.
The water level went so high, it pushed oil up thru the intake manifold, and out the carb, coating the top of the intake slightly. All while sitting on a trailer over a 2 year period. WTF? I am perplexed.
Coolant still green, and pressure tested fine. It is raw water in the oil.:huh:

Pretty hard to get all that water into the engine from rain if the arrestor was on the carb and the engine cover in place.
Carb and exhaust are the only way it can get in.
Did the perhaps whole inside of the boat fill up with water on the trailer?

I've gotten a few engines over the years that have been submerged up and running but the key is to either keep them full of water or get them running right away after the water is out. If there is a lot of rust inside, it wouldn't have cranked over.
You've go hopes, good luck. :thumbs:

 

[big2bird]

Frankly Noonie, I bet someone jambed a water hose it the oil filler, and filled it up. Sabotage. It was full all the way to the top of the exhaust manifolds, right below the riser elbows.

 

[010752]

Well, that would certainly explain it.
On the bright side, all the electrics are saved and with a few oil changes, it should be good to go.

 

[TimAT]

Since it obviously never ran full of water, a good flush and it should maybe be OK. The closed cooling system helps- especially since there's no sign of coolant in the oil. Straight water is pretty much survivable. Unless it runs long enough to eat bearings. Now the trick is to find how it got in there in the first place.

 

[big2bird]

I pulled the risers today, drained the coolant, drained out the water/oil/goo, and sent the owner out for parts.
Hell, he even got a flat on the freeway towing it over here. Had to rescue him with my floor jack.:cussing:
Now, while poking around, I found the oil/goo floated up high enough to come out the top of the carb, out the arrestor, and on top of the intake.
I 'll have to rebuild the carb before I can start it.
I'm sticking to Vettes. At least the fiberglass is on the correct side.:nuts: