Numpty engine question - brief run with no coolant

[MikeBz]

Newly acquired boat is being launched tomorrow. Engine (Yanmar 2GM) was serviced & winterised in October, dewinterised in April. I'd like to prove that it runs before we're hoisted in - is it OK to start it up for a few seconds on dry land with no coolant supply? Could poke a running hose into the water intake fitting but I doubt that'll do much good. I suppose the impeller is the worry?

Mike

 

[MoodySabre]

A hose up the inlet is OK but don't keep it up there if the engine won't start and just turns over or you could fill the exhaust and flood back into the engine. I used to leave the seacock shut and put the hose in the strainer but on some boats this would risk soaking everything. Alternatively you could take the impeller out. The engine won't overheat for a few minutes.

 

[boatmike]

A hose up the inlet is NOT OK don't do it! There is a danger of creating a flow through the engine, filling the exhaust, and creating a backflow into your valve gear wrecking the engine. What IS OK is having the inlet pipe lead into a bucket of water and letting the engine draw water from that with a hose keeping the bucket topped up. There are some pump impellors (available from ASAP supplies) that are made out of self lubricating urethane and will stand running dry for a few minutes but if you have not got one of these even a short burst with no water will wreck a standard rubber one. If you take it out of course you can run for a very short burst OK without harming anything else.

 

[DavidGrieves]

Hi

Some good advice from the other posts. It is OK to run engin with hose up the intake, get somebody to help you, as soon as the engine starts push the hose into the skin fitting( a rag wrapped around the hose helps it seal).Putting the intake hose into a bucket is a safer method because you are not forcing water through but allowing the engine to take what it need as if it was in the water. On my boat the galley sink is close to the strainer, the sink drain hose is long enough to reach the raw water strainer. I fill the sink, start engine, pull plug out of sink, turn tap on and ballance the flow. You can always put a hose pipe into the water tankk filler or sink if you need it running for longer.

One day I intend to put a "tee" and a ball valve into the system so I can flush it out with fresh water after use. It's an old raw water cooled engine and I guess fresh water lying in the water ways for long periods can only extend its life??? The "jobs to do" list keeps getting longer. /forums/images/graemlins/ooo.gif

 

[davidbains]

I just did the same with my 2GM20 by lowering a water jerry can into the engine bilge and sticking the end of the saltwater intake hose into said can. Lasts a few minutes, long enough to warm up the oil to change it easily.
What exactly was done to "winterise" your 2GM20?

 

[MikeBz]

Thanks for all the excellent advice.

Winterisation was done before we got our hands on it, but as far as I can tell from the invoice it was flushed through and filled with anti-freeze (it is raw water cooled), cleaned down and sprayed with duck oil (poor duck). This was in addition to the normal service items (oil/filter/impellor change etc.)

Mike

 

[Guest]

Take care of the vibration. I no not know how you boat is stayed. But the dampening affect of the water will not be present. If the stays rely on friction do NOT do it.

If the engine cooling jacket is full of water then leave it full. But I would not start it with no water around the cylinders.

 

[youngwrinkley]

FWIW At the end of the season, when ashore, I used to flush my engine out by connecting it up to the boat's fresh water tank. - Empties the tank as well

 

[Spyro]

Running with no coolant will not harm the engine but will destroy the impeller and possibly burn/melt the exhaust hose as there is no cooling going through the mixing elbow. Easiest method is to get a longer length of hose pipe and connect one end to the inlet side of the pump and another in a bucket of water. If you have to you can keep filling the bucket with water as required. You may have to fill the hose with water before connecting as the pump may need primed. This will tell you that your pump/impeller is working OK

 

[catmandoo]

I stuck a hose into the inlet but took it from a bucket of water on a stool . I then connected a hose from the water supply tap to the bucket and adjusted the flow so that the bucket would overflow .

This was very successful but a little bit wet . Idea was that there was a storage capacity/time lag available if the hose fell out

 

[Avocet]

I wouldn't worry about the exhaust for a minute or two under no load. I regularly run my 12HP diesel up without the impeller in but with no water (other than what's in the jacket) and it doesn't seem to do any harm. I agree about possible impeller damage though.

 

[chrishelen]

Hi i would NEVER run a liquid cooled engine without coolant not even for one minute! thats what the coolant does ,cool the engine, also i would use a bucket every time with the inlet pipe sucking out what it needs and a hose keeping the bucket full,if you get water in the cylinder even an eggcup full it will do a lot of damage because you cant compress water, also running you engine ashore,keep it in short runs not more than 5 mins the vibration wont do the boat any favours. chris.

 

[Searush]

My current engine (recent Yanmar 3gm) has a heat exchanger so can be run using permanent water in cooling system - just like running a car with the radiator covered up. I suspect yours is similar.

My previous engine was raw water cooled so was simply drained in the winter - no water to put anti-freeze into! For pre-launch check & to prime system I used a bucket of sea water poured slowly into the top of the sea water inlet filter. As the engine ran this was flushed thro the system & out of the exhaust exactly as if in the sea. Only ran for a minute of two anyway, but guranteed I could start her up & motor away as soon as the slings were released. Those whose engines failed ended up running round panicking trying to get towed, or warped out of the way of the next boat coming in!

 

[Guest]

[ QUOTE ]
A hose up the inlet is NOT OK don't do it! There is a danger of creating a flow through the engine, filling the exhaust, and creating a backflow into your valve gear wrecking the engine. What IS OK is having the inlet pipe lead into a bucket of water and letting the engine draw water from that with a hose keeping the bucket topped up. There are some pump impellors (available from ASAP supplies) that are made out of self lubricating urethane and will stand running dry for a few minutes but if you have not got one of these even a short burst with no water will wreck a standard rubber one. If you take it out of course you can run for a very short burst OK without harming anything else.

[/ QUOTE ]

Disagree ... I have run engines without trouble with closed seacocks, opened strainers and a hose stuffed in.

a) have hose turned of at engine end ready to turn on.
b) start engine and let settle
c) poke hose into strainer top and open water to a reasonable flow but not full (about half is ok with std uk pressure)
d) do not seal hose into strainer ... let it overflow if too much water going in
e) turn of water and extract BEFORE stopping engine
f) Bobs proverbial mums brother.

You can use same technique to pass anti-freeze through engine for winter layup ...

Trick is to not have too much pressure and also not to fill system when engine not running.

As to running dry ... ask any mechanic in a yard if he runs up an engine dry ... bet most say yes - but only short time. I know when mine was being sorted this winter - it must have been run 4 or 5 x dry ... last one was for quite a long run as well ... engineer just saying ... no problem - its fine.

 

[chrishelen]

why not just use a bucket and let the engine use what it needs? remember kiss?

 

[Guest]

Answer to KISS ....

Cause its easier to climb a ladder with a hose end than a bucket ... even if bucket is empty - as you then have to bring a hose as well.

My way - is just a hose and thats it. AND I can run engine as long as I want..... without filling a bucket...... again and again ....

KISS ... /forums/images/graemlins/wink.gif

The only reason I made a longer post than just say use a hose - was for any newbies out there to gain a bit of knowledge about not filling systems with engine not running etc. etc. and not sealing hose into inlet etc. etc.

KISS ...... /forums/images/graemlins/wink.gif /forums/images/graemlins/wink.gif

 

[chrishelen]

Re: Answer to KISS ....

yes but you climb the ladder with the hose and guess what the BUCKET is already in the boat so you just put the hose in the bucket TURN the hose on put the engine water intake into the bucket, and what do you know when the engine is running the water stays in the bucket if you tweak the flow right,KISS.

 

[Guest]

Re: Answer to KISS ....

[ QUOTE ]
yes but you climb the ladder with the hose and guess what the BUCKET is already in the boat so you just put the hose in the bucket TURN the hose on put the engine water intake into the bucket, and what do you know when the engine is running the water stays in the bucket if you tweak the flow right,KISS.

[/ QUOTE ]

DING DING Seconds out .... round 2 ....

but you forget that my boat is over 30 yr old and to get the intake pipe of the strainer would mean probably breaking it ! OOOPs - shouldn't have admitted that - now I'm in for it !!

 

[chrishelen]

Re: Answer to KISS ....

ok nigel,lets put this one to bed,but what if you need to get at the strainer would you need to break the hose then? chris.by the way my boat is also 30 years old and made of wood,but the engine is a 20 year old volvo, regards.

 

[Guest]

Re: Answer to KISS ....

[ QUOTE ]
ok nigel,lets put this one to bed,but what if you need to get at the strainer would you need to break the hose then? chris.by the way my boat is also 30 years old and made of wood,but the engine is a 20 year old volvo, regards.

[/ QUOTE ]

No I would not as the strainer is a vertical cylinder to the skin fitting valve .... engine take off is to the side. So in fact I can do all except remove whole from hull without disconnecting engine pipe. In fact the garden hose is inserted into the top of the vertical strainer part ... not the engine hose.

To do with a bucket or other way would mean extra work for me in a cramped space. a) I would have to create a connection / pipe from bucket to engine hose as strainer cannot be used as no suction would be created without sealing that connection together. Second why complicate when a hose stuck in top of open strainer supplies total needs for as long as water is available to the hose ?

I am not arguing against using a bucket ... it works ... but a hose is 50ft away from my boat, and is easiest way for my set-up and I suspect for many others ...