Cranking raw water cooled the engine too much then vapor or smoke

[redtim]

Hi All!

I'm new to the atomic 4 game, and have an exhaust related question.

Starting up the engine for the first time on a new boat I neglected to open the valve on the fuel line and cranked for a while without the engine turning over. It was probably around a minute give or take total cranking time. Eventually figured out what was up, and got the thing running. The next day I got this in an e-mail
Important! If for some reason you have to crank the motor a bunch make sure to close the raw water intake otherwise it sucks water back up into the exhaust manifold and mucks things up.

Fast forward to the next trip out, first extended test under load, the engine ran fine for 20 minutes or so, then started to stumble, then die. Next time, a little longer, but similar symptoms. These I was attributing to bad gas, which I changed out last week, and started up, ran under load at the dock for about an hour no issues, but I did notice a lot of white smoke or vapor coming out of the exhaust. I believe it's vapor because it dissipates relatively quickly. The vapor is pretty minimal under low to moderate load, somewhat typical for

My question
Does it sound like water has backed up into the exhaust manifold?

If so, What do I do about it?

Thanks

tim

[Dave Neptune]

Tim, it blew out when you got it running. Cranking for extended "STARTING LIKE TIMES" can cause a build up of water in the "exhaust" of which can back up far enough to flood the exhaust manifold, no biggie. The biggie is that an open exhaust valve or two may let the water into the cylinders and on into the oil~~ big mess and possible seizing of the engine!!!

Dave Neptune

[tenders]

If the engine starts readily and runs for 20 minutes at a clip before stumbling and dying, it isn't exhibiting obvious signs of a manifold problem. But you might want to check for a stuck valve or head gasket issue by removing the spark plugs one at a time (carefully, so you don't get zapped) and seeing if the engine slows down for each one. If the engine sound doesn't change, you know there's something wrong in that cylinder.

But your symptoms sound more to me like a failing coil. Other possibilities include a failing condenser (unless you have electronic ignition, which I think is a no-brainer upgrade), a clogged fuel filter, or a failing fuel pump.

[redtim]

Thanks! The engine was just rebuilt, so i'm hoping its not something serious,

for reference, here's a video of what's coming out at a moderate load

https://www.youtube.com/watch?v=dvNqbzZeCMw

[redtim]

Also, no water in the oil, first place I checked...

It seems to be running well now, just the smoke/vapor coming out has me concerned

[hanleyclifford]

Thanks! The engine was just rebuilt, so i'm hoping its not something serious,

for reference, here's a video of what's coming out at a moderate load

https://www.youtube.com/watch?v=dvNqbzZeCMw

That is not enough water coming out. Check for restrictions in the raw water circuit.

[romantic comedy]

You checked for water in the oil, right?

[BunnyPlanet169]

That is not enough water coming out. Check for restrictions in the raw water circuit.

I agree - and that's steam from something too warm.

Do you have a temperature gauge, and what's it reading?
Does the water flow change if you play with the bypass valve? Do you have a bypass valve?

[JOHN COOKSON]

I agree - and that's steam from something too warm.

Another +1.
You shouldn't be getting batching at "moderate load" RPMs. You should only see batching at idle RPMs.
Here's what to do.
Leave the hose attached to the outlet fitting on the manifold but disconnect the other end and aim it out into the cockpit or into the bilge. Start the engine and rev it up a bit. Water should come out like a garden hose. Don't melt any plastic mufflers while doing this. If you aren't getting enough water through the engine there is a restriction to the flow through the engine or you have a failing water pump. Report back. We'll you what to do next.

TRUE GRIT

[redtim]

You checked for water in the oil, right?

Yep, the oil looks fine

[redtim]

I agree - and that's steam from something too warm.

Do you have a temperature gauge, and what's it reading?
Does the water flow change if you play with the bypass valve? Do you have a bypass valve?

Yeah, the temperature at idle is around 140 at moderate load climbs to around 170

Not sure about the bypass valve, I'll take a look when I get over to the boat tonight.

[redtim]

Another +1.
You shouldn't be getting batching at "moderate load" RPMs. You should only see batching at idle RPMs.
Here's what to do.
Leave the hose attached to the outlet fitting on the manifold but disconnect the other end and aim it out into the cockpit or into the bilge. Start the engine and rev it up a bit. Water should come out like a garden hose. Don't melt any plastic mufflers while doing this. If you aren't getting enough water through the engine there is a restriction to the flow through the engine or you have a failing water pump. Report back. We'll you what to do next.

TRUE GRIT

Thanks, will give this a shot.

[redtim]

Another +1.
You shouldn't be getting batching at "moderate load" RPMs. You should only see batching at idle RPMs.
Here's what to do.
Leave the hose attached to the outlet fitting on the manifold but disconnect the other end and aim it out into the cockpit or into the bilge. Start the engine and rev it up a bit. Water should come out like a garden hose. Don't melt any plastic mufflers while doing this. If you aren't getting enough water through the engine there is a restriction to the flow through the engine or you have a failing water pump. Report back. We'll you what to do next.

TRUE GRIT

Ok! Pulled the hose off, and the water was running out pretty evenly like a garden hose

[redtim]

I agree - and that's steam from something too warm.

Do you have a temperature gauge, and what's it reading?
Does the water flow change if you play with the bypass valve? Do you have a bypass valve?

I don't see a bypass valve, the line runs straight from the water pump to the thermostat.

[Easy Rider]

Tim,
There is a "T" fitting on the hose between the water pump and the thermostat. The "T" fitting is where the cooling water enters the block and the volume is controlled by the thermostat. If you have a by-pass valve it would be located between the "T" connection and the thermostat. They are an aftermarket product and are available from our host. Some of the guys here who have lost faith in their thermostats or like to have a manual means of controlling the temperature have installed them and from all accounts like them.

Just a way out thought, but if your located where the outside temperature is cold you could be exhausting some condensation as part of what we can see.

Chuck