Flooding an engine...???

[Tomahawk]

Have just had a very bad afternoon... Yanmar 3GM fresh water cooled

Tried to start the engine.. nothing doing..
Then I realised that the fuel was turned off as I had cleaned the filter... OK silly me..

Tried again.. still nothing doing.. engine turning over quite nicely but no start.. I wondered if I had managed to get an air lock in the fuel lines so I cracked open the injectors.. ... not things got confusing.. no fuel in the injector pipes.. yet the stop lever is fully over to the run position???? So a problem with fuel here ...

Then suddenly there is water flowing out of the inlet manifold..
Took out the injectors and water in all three pots..

Have I simply flooded the exhaust manifold by cranking for too long with the seacock open???

Have filled the pots with oil for best as I can to prevent rust??

Help please?

 

[sailorman]

Have just had a very bad afternoon... Yanmar 3GM fresh water cooled

Tried to start the engine.. nothing doing..
Then I realised that the fuel was turned off as I had cleaned the filter... OK silly me..

Tried again.. still nothing doing.. engine turning over quite nicely but no start.. I wondered if I had managed to get an air lock in the fuel lines so I cracked open the injectors.. ... not things got confusing.. no fuel in the injector pipes.. yet the stop lever is fully over to the run position???? So a problem with fuel here ...

Then suddenly there is water flowing out of the inlet manifold..
Took out the injectors and water in all three pots..

Have I simply flooded the exhaust manifold by cranking for too long with the seacock open???

Have filled the pots with oil for best as I can to prevent rust??

Help please?

how long were you cranking

 

[Tomahawk]

A good five minutes worth..
Is that enough to fill the exhaust pipe ?
It dis appear to be very full of water when I opened everything..

PS .. many thanks

 

[stuey_two]

Bad luck, Tomahawk, you've hit a known problem with watercooled marine engines. If the engine is turned over too many times without firing, the water lock fills with sea water which back-flows into the exhaust manifold then into the cylinders.
Propmpt action is highly desirable.
In your case the salt water has not sat there long so you may get away with little or no damage so long as you sort out the problem quickly. Nigel Calder's Diesel Engine book tells you how but the basics are to drain out the water lock, close off the engine seacock and turn the engine over a few times to expel water from cylinders. Then try to restart the engine as normal. If it won't start, follow your usual "engine won't start" procedures.
After you get it started. don't forget to open the seacock then warm the engine up thoroughly before stopping it. This will evaporate any seawater that may have got into the oil.
An oil and filter change asap is recommended. With any luck, that's all you will need to do.

 

[Jcorstorphine]

Watch out for Hydraulic lock

Bad luck, Tomahawk, you've hit a known problem with watercooled marine engines. If the engine is turned over too many times without firing, the water lock fills with sea water which back-flows into the exhaust manifold then into the cylinders.
Propmpt action is highly desirable.
In your case the salt water has not sat there long so you may get away with little or no damage so long as you sort out the problem quickly. Nigel Calder's Diesel Engine book tells you how but the basics are to drain out the water lock, close off the engine seacock and turn the engine over a few times to expel water from cylinders. Then try to restart the engine as normal. If it won't start, follow your usual "engine won't start" procedures.
After you get it started. don't forget to open the seacock then warm the engine up thoroughly before stopping it. This will evaporate any seawater that may have got into the oil.
An oil and filter change asap is recommended. With any luck, that's all you will need to do.

Just to add to your worries, there is always a concern over a hydraulic lock in the cylinders as water is not compressible. I had this on a 12 cylinder 1000 HP Rolls Royce diesel where the exhaust had let in water while the engine was stationary as the sump was full of water. Rather than crank it after we drained the water and replenished the oil, I removed all of the injectors and then cranked it to expel water from the bores.

 

[philip_stevens]

Diesel engines on marine/cargo/passenger ships are "blown" over before putting fuel on, with the cocks opened to the cylinders to ensure there is no water in the cylinders.

On a small diesel engines, one way to ensure there is no water in the cylinders is to remove the injectors and turn the engine over de-compressed to expel any water that may be in the cylinders. Alternatively, with the seacock closed, turn the engine over de-compressed. This will expel any water that may be in the cylinders.

In all other aspects, do as previously advised. Especially run the engine to heat it up and then change oil and filters - perhaps twice.

 

[Jabamusic]

..............then let us all know how you got on.

Good Luck

 

[Spuddy]

I might have unknowingly done the same and only suspected that this was the case after exhaustive delving into starting problems eventually showed that con rod was bent. This effectively changes the injector timing and so affects starting. Just an observation in case you find starting more of a problem

 

[Tomahawk]

finger crossed

I must to down to the engine again..
To the lonely oil and muck
And all I ask is good fortune
it runs again with luck... (with apologies where due)




Many thanks everyone for your help. I worked out what had happened last night thinking things over..
Will post later to tell what I find .... fingers crossed

 

[Tomahawk]

very confused

Well I got the water out the engine..

But there is no fuel in the injector pipes???? I have fuel all the way to the fuel pump .. clean filters but nothing doing at all...

It seems as if the stop lever is still on the off position.. I have checked stop the lever on the side of the fuel pump. It is in the correct run position..

I am wondering if the stop has come adrift inside the fuel pump?

 

[Jcorstorphine]

Well I got the water out the engine..

But there is no fuel in the injector pipes???? I have fuel all the way to the fuel pump .. clean filters but nothing doing at all...

It seems as if the stop lever is still on the off position.. I have checked stop the lever on the side of the fuel pump. It is in the correct run position..

I am wondering if the stop has come adrift inside the fuel pump?

Have you tried cranking the engine with the high pressure fuel pipe to the injector left open i.e. not connected to the injector to see if there is a pressure pulse.

 

[DavidGrieves]

You need to get all the water out of the cylinders. Take out ALL the injectors and turn engine by hand (if poss). Use a hair dryer with a hose/tube attached aimed into the cylinders to dry inside the cylinder. Spend some time doing this. When you refit the injectors, turn the engine by hand if you feel any resistance you may have hydraulic lock and water still in the cylinders. When the engine is turning over by hand you now need to bleed the fuel system. Get all the air out working from tank to injectors. As you have already mentioned, you need to eliminate the engine stop, make sure it is retuning OK.

Might be worth checking engine oil too. If it is higher than normal or showing signs of emulsion it may be worth changing.

Your exhaust hose will probably be full of water too. Drain it down from your water lock.

When you try to re-start the engine keep the seacock closed but as soo as it starts open it QUICKLY (get a friend to help).

Water in the engine is not the end of the world, but you do need to act quickly...

 

[Bobobolinsky]

I must to down to the engine again..
To the lonely oil and muck
And all I ask is good fortune
it runs again with luck... (with apologies where due)




Many thanks everyone for your help. I worked out what had happened last night thinking things over..
Will post later to tell what I find .... fingers crossed

Bad luck mate, I did have a last line change if it didn't start, but you can work that one out yourself

 

[jakeroyd]

This may have been coverd by other posters but have you bled the fuel system properly ?
On the fuel lift pump there should be a manual lever or trigger.
By operating this by hand you can deliver fuel to the system.
There is a bleed screw on top of the fuel filter and another one downstream from the injectors.
Slacken these slightly whilst pumping with the trigger.
If there is air in there you will see it being expelled , once there is only fuel nip them up , job done.
Then again whilst operating the lift pump manually , crack off each union nut on each injector and let any air out there.

 

[charles_reed]

Sounds as though it just requires a good bleed.
Start with getting the air out of the lower system, by using the bleed on top of the fuel filter and the manual on the lift pump. When that has no more bubbles coming out, slacken off the #1 injector pipe until you get air-free fuel coming out, then go on through #2 and #3.
It's a long, smelly and messy job, and don't use the starter for more than 15 secs.
The water-lock problem is possible but IMHO unlikely.
Later (YM) series are like modern diesel engines, self-bleeding. You should have, on the GM series, a compressor valve on each cylinder which will allow you to check any raw-water ingress.

 

[Graham_Wright]

This has provoked fears of my own. I can understand that cranking the engine without it firing can introduce a lot of water which is not being expelled by exhaust gases, but surely if you close the sea valve you will wreck the pump?

I have just acquired a very well engineered anti syphon device for the exhaust injected raw water but it has a significant capacity. This could exacerbate the waterlock introduced problem.

Would a better solution be to disconnect the drive to the Jabsco until the engine fires? Not an easy solution if it isn't fitted with a clutch.

Alternatively, could the output from the Jabsco be diverted past the heat exchanger and not into the exhaust outlet until the engine was running? I guess it would be easier after the heat exchanger as the pipework is simpler.

Or do I worry too much?

As an afterthought, what is the function of the waterlock? I have one fitted because Mr Vetus said so but I never questioned the reason.

 

[sailorman]

This has provoked fears of my own. I can understand that cranking the engine without it firing can introduce a lot of water which is not being expelled by exhaust gases, but surely if you close the sea valve you will wreck the pump?

I have just acquired a very well engineered anti syphon device for the exhaust injected raw water but it has a significant capacity. This could exacerbate the waterlock introduced problem.

Would a better solution be to disconnect the drive to the Jabsco until the engine fires? Not an easy solution if it isn't fitted with a clutch.

Alternatively, could the output from the Jabsco be diverted past the heat exchanger and not into the exhaust outlet until the engine was running? I guess it would be easier after the heat exchanger as the pipework is simpler.

Or do I worry too much?

As an afterthought, what is the function of the waterlock? I have one fitted because Mr Vetus said so but I never questioned the reason.

Yes
there is no water to a pump when newly launched is there, by isolating the inlet there is still water within the pipe & how long does it take to open a valve say 10 secs

 

[Graham_Wright]

Yes
there is no water to a pump when newly launched is there, by isolating the inlet there is still water within the pipe & how long does it take to open a valve say 10 secs

That's made it worse!

"there is no water to a pump when newly launched is there" er, non capsico!

But there is air rapidly, displaced by water as soon as the pump turns.

"how long does it take to open a valve say 10 secs". The problem revolves around prolonged cranking without firing. What happens to the impeller when cavitation starts? I don't know.

However;- a positive suggestion. If the outlet from the anti-syphon lock is closed, the pumped water could escape through the syphon hole provided it was big enough. That appeals to me but, as usual, I haven't thought it through. Over to the experts.

 

[vyv_cox]

You will do no damage to the pump at starter motor speeds, particularly as it will already be wet from previous cranking. Close the valve until the engine fires, then open it. As Sailorman says it will come to less harm like this than when you first launch. I have had a persistent failure of the pump to prime after sailing in boisterous conditions. Sometimes the engine has run for 30 seconds before being stopped to prime manually. I have never failed an impeller yet.

Your positive suggestion - surely the anti siphon lock is higher than the engine? So having filled the engine, the water will then pass through the hole.

 

[Graham_Wright]

You will do no damage to the pump at starter motor speeds, particularly as it will already be wet from previous cranking. Close the valve until the engine fires, then open it. As Sailorman says it will come to less harm like this than when you first launch. I have had a persistent failure of the pump to prime after sailing in boisterous conditions. Sometimes the engine has run for 30 seconds before being stopped to prime manually. I have never failed an impeller yet.

I'm getting there! I guess that the back pressure on the vanes of the impeller will cause them to deflect to release that pressure thus avoiding harm. Does that seem reasonable?

Taking your point about not priming - how did you know it wasn't pumping? Are we back to the anti-syphon valve spurting?

If you start the engine from topsides, closing the sea valve is possibly not possible.

I'm worrying again!