Running your engines without water ??

[syd]

Hi all
I was perusing the hard yesterday and was drawn toward the gurgling purr of a twin engined turbo diesel motor boat up on blocks which had no water feed to either engine. On further noseyness I had a natter with the owner who had removed the Jabsco impellors and was running the engines up to temperature with only the fresh water. The engines are turbo charged and aftercooled. Once they had reached their running temp he simply switched them off.
Would this damage the engines or cooling system?
Syd

 

[steverow]

Without water

Dunno, I'd been wondering that myself.
As long as the impellors are'nt in then I cant see that there's owt else to damage.
Bit like a car I suppose just run it up to temp and make sure it doesnt go over then everything should be OK.
Might try this myself in the new year since I have boat on a trailer at home.
Mind you, not difficult to shove a hose up the raw water input anyway.

 

[ulyden]

Have done that a lot of times myself. As long as the water is circulating and not boiling it is no problem! The water is circulating internal as long as the thermostat is closed! The charge air cooler is without water that is ok.

If you run it for a long time and the oil cooler is sea water cooled, the oil might get hot! Normaly the oil take a loger time than the cooling vater to get hot! But on modern direct injektion engines the efficancy is very high an the loss to cooling water low!

 

[MarieK]

would be very interested to hear other peoples views on this. Would the water pump running without being under any load (ie no impellor) be a potential problem?

 

[l'escargot]

I wouldn't see any problem with there being no load on the pump but I would be concerned about the exhaust temperature and the effect it could have on plastic goose necks, water traps etc.

 

[Whitelighter]

Having seen the damage done by running an engine with the inlet cock turned off toa silencer in the exhaust system I would not reccomend it.

And this was damage after just a few minutes...

 

[[2068]]

On my engine (KAD32) sea water gets sprayed into the exhaust to cool it down. I've never tried it, but running for any length of time without sea water might end up with crispy exhaust pipe or exhaust manifold.

 

[ulyden]

On my engine (KAD32) sea water gets sprayed into the exhaust to cool it down. I've never tried it, but running for any length of time without sea water might end up with crispy exhaust pipe or exhaust manifold.

The rubber on this might be of different quality. I use 180deg C spes
but I have seen 100deg spes. Normaly the exhaust temperature of an ideling diesel engine is low! Om a petrol lambda one engine it might be hi! Also remember if you have a drive!

The best ting is to connect a water hose to the sea water inlet vile doing this!

But you dont harm the engine!

 

[volvopaul]

Not a good idea, 2 things spring to mind.

1 no water on the water pump shaft seals to cool the seal likely the seal will leak water out when its put back in the water.

2 exhaust rubber hose will delaminate and cause a blockage, or leak water, damage to plastic silencer, to name but a few so not a good idea.

Some marina will not alow engines to be run for fear of the vibration through the hull allowing the props and stays to be vibrated loose may cause the boat to move on the hardstanding.

 

[Divemaster1]

Would agree with my fellow Norwegian on this (Velkommen inn hit forresten Ulyden!!)..

No damage to engine, but you need to know your auxillary systems, including your exhaust systems etc. If in doubt don't do it ..... and do connect a waterhose if you have an impellor installed in your raw water pump..

 

[VicS]

As said pump seals could suffer but if they were actually still wet maybe they would survive.

The biggest threat is as pointed out to the exhaust system if run for long enough for the engines to reach normal working temp.

 

[hlb]

Why do folk want to start engines. that arnt going anywhere. Apart from changing oil, I cant think of one good reason and never met the mechanic that would start an engine on the hard.

Yes they need starting when serviceing Or looking for leaks. But starting for no reason only dose them harm.

 

[Firefly625]

Why do folk want to start engines. that arnt going anywhere. Apart from changing oil, I cant think of one good reason and never met the mechanic that would start an engine on the hard.

.

....I was thinking the same! There does seem a huge amount of people who love to start there engines whenever possible, they sit on their moorings busy polishing there bores for an hour and then switch off and go home, usually they are also the ones that give the throttles a good blip before switch off to ensure maximum damage is done to the engines.....!

 

[omega2]

not a thing I would do, we had exhaust pipes delaminated over years of use, but the final nail in the coffin was when the raw water pipe blew off the exhaust elbow, causing complete blockage and then blowing off the exhaust pipe at the elbow, and filling the boat, all this happened inside 30 seconds. Luckily we had bath towel to stick up the outlet, and arms long enough to reach it.