Running an inboard diesel ashore without cooling water?

[Rayjive]

Is it safe to start up and run a direct raw water cooled diesel engine (Yanmar 2GM20) ashore without connecting to a cooling water source for say 10 or 20 seconds? It's just to be able to check that the engine starts up prior to launching.

 

[VicS]

Is it safe to start up and run a direct raw water cooled diesel engine (Yanmar 2GM20) ashore without connecting to a cooling water source for say 10 or 20 seconds? It's just to be able to check that the engine starts up prior to launching.

If its dry the water pump impeller could be damaged. Take it out, if running without it is OK, or lubricate it.

If you run for a bit too long rubber and plastic bits of the exhaust system will suffer .

 

[prv]

I wouldn't.

The engine won't overheat, and the impeller would probably be ok - and in any case on this engine you can remove the small belt so the pump doesn't spin. However, the big problem will be the exhaust. Without water injection, you will be chucking hot gas (it's burned, so it will still be hot even before the metal of the engine warms up) directly into a rubber hose connected (usually) to a plastic water trap. Neither of these materials like having hot gas blown into them. The inside of the hose can char and fail even while the outer looks ok.

Pete

 

[vyv_cox]

You may get away with it for 20 seconds but the risk is that you could exceed this time for a variety of reasons. What I do is use my Vetus strainer as a reservoir. It is sited above the pump and normal water level as per instructions. Remove the lid and pour in water to the top. Start the engine and keep pouring water while the engine runs. At fast tickover 11 litres will give you well over a minute to flush through at the end of the season or to check before launching. Or you could use a hose pipe with pistol nozzle if there is one handy.

 

[Avocet]

I've done it plenty of times before on Avocet's single cylinder raw water cooled 12 horse engine. As has been said, the impeller won't like it (and unless you know it's wet in there, it's likely to suffer), but the exhaust has always been fine. There's about 2' of rubber exhaust hose, then a plastic waterlock, some more hose, a plastic muffler and a rubber swan neck. The rubber immediately downstream of the elbow doesn't even get hand-hot in 10 seconds.

 

[macd]

Providing you ensure the impeller is not going to suffer, it'll probably be OK for 15 seconds or so.

However, a straightforward means of running the engine without seawater is a great convenience -- to run antifreeze through for winterising, if nothing else. If you lack a strainer such as Vyv's (post #4), knock up some means of detaching and then extending the inlet hose into a bucket; then top up the bucket to keep water running through the engine. (For winterising, you'd put antifreeze/corrosion inhibitor in the bucket.) But do not connect any mains hose direct to the intake: you'd stand the risk of back-filling the cylinders. You can imagine what that would do if left for six months.

Then, next time you winterise, you'll have all the right bits to hand (well, maybe buried in a locker somewhere, but you know what I mean).

 

[ffiill]

If you have indirect cooling then its far less of a problem so long as you disconnect raw water pump from system-in my case just remove its drive belt.The heat exchanger also cools the exhaust manifold which anyway is cooler than one on a petrol engine.
I usually run for several minutes but be warned:
Last winter I changed my antifreeze as I do annually after having used the engine block drain and flushed out the block.
I refilled and ran the engine up for several minutes as I did again in the spring shortly before putting the boat back in the water.
The yard launched my boat and off I set to my mooring at Plockton some 5 miles away.The temperature guage went up to normal and continued up to boiling point.
I limped back to the launch cradle where I found the heat exchanger header tank empty.As I once destroyed a 4x4 cylinder head block I immediately diagnosed the problem as an air lock inside the engine water ways which hadnt had chance to clear with the two minute runs.If I had allowed engine to warm up before setting off of course the problem would have become apparent.

 

[MASH]

Just plug a hosepipe up the through-hull water inlet, or feed one into the strainer in the engine bay. My yanmar 3YM couldn't pump the flow rate of a normal domestic hose when fed into the strainer so it isn't an issue.

Easy!

 

[black mercury]

If you are going to plug a hose pipe into the through hull make sure you have someone to turn the water on as the engine starts. Don't turn the water on and then get on board to start the engine because the water will fill the exhaust and then it will fill the engine.

 

[david_bagshaw]

Just plug a hosepipe up the through-hull water inlet, or feed one into the strainer in the engine bay. My yanmar 3YM couldn't pump the flow rate of a normal domestic hose when fed into the strainer so it isn't an issue.

Easy!

+1 and allow the excess to drain away.

Have run 6 cyl 150 hp engines this way , along with 3 cyl generator, and a single cyl farryman powered gen set.

The trick is to ensure the water flow establishes through the sea water pump, & in the case of the indirect genny, not run at full power, incase the supply is interrupted. Great for shore layups on the coast as removes all salt water.

A stand pipe in the filter helps if it is the vetus type.

 

[Jamesuk]

Is it safe to start up and run a direct raw water cooled diesel engine (Yanmar 2GM20) ashore without connecting to a cooling water source for say 10 or 20 seconds? It's just to be able to check that the engine starts up prior to launching.

No, I ran a genset 12kw for the first time after the "shore" guy said, Ill keep the genset ticking over using cooling water straight into the raw water system throughout the winter. It shredded to pieces within seconds of starting it. Then I had to go through the hassle of finding the blades in the system.

I would agree with one of the other posters by taking the impeller out and then running it. Really tho, I just wouldnt run in, unless you can provide the cooling water for it and put it under load for an hour. In some marina's they do have options for "live aboards".

Good luck.

 

[CAPTAIN FANTASTIC]

You can test start the engine without water for as long it is just that "test start"; I do it often. My Volvo rubber impeller which I replaced a few days ago, was at least 7 years old.

 

[Scotty_Tradewind]

What I do is use my Vetus strainer as a reservoir. It is sited above the pump and normal water level as per instructions. Remove the lid and pour in water to the top. Start the engine and keep pouring water while the engine runs. At fast tickover 11 litres will give you well over a minute to flush through at the end of the season or to check before launching. Or you could use a hose pipe with pistol nozzle if there is one handy.

+1
with a hose keeping the strainer topped up it provides the engine with the correct amount of water and so can be run for as long as you wish.
Speed up the engine= speed up the water from the hose.

If you have no strainer you can open up the impeller and either remove the impeller or smear silicon grease in and around the impeller blades for that short run you speak of.

Only put in gear if you have a water supply going through or around the stern gland. My twister had a water fed stern gland and so running it slowly in gear on land gave it the required lubrication

 

[Spyro]

If you are going to plug a hose pipe into the through hull make sure you have someone to turn the water on as the engine starts. Don't turn the water on and then get on board to start the engine because the water will fill the exhaust and then it will fill the engine.

Would it get past the impeller ?

 

[vyv_cox]

Would it get past the impeller ?

Yes. Water pressure can easily deflect the vanes that are angled away from the inlet.

 

[pheran]

Some years ago a guy in our marina started up the 4-cylinder diesel in his little river cruiser, revved it up and promptly vibrated the boat off its stands. Luckily, no one was seriously hurt, and because it was standing on grass, very little damage to the boat. But there it had to stay for the whole of the winter until the hired in crane came back for the general lift-in. A salutary lesson perhaps..............

 

[prv]

Some years ago a guy in our marina started up the 4-cylinder diesel in his little river cruiser, revved it up and promptly vibrated the boat off its stands.

+1 - our yard is not particularly happy with people running engines ashore for this very reason, though I don't know if it's outright prohibited. I wasn't worried with Kindred Spirit because her long keel and bilge fins meant she couldn't really fall over whatever happened, but I'd be a bit more circumspect with a fin keeler on props and an older more bouncy engine.

Pete

 

[MM5AHO]

I do this every year. I disconnect the hose from strainer to seawater pump, and put the end in abucket of water. The sea water pump sucks up the water from the bucket, and I use a garden hose to refill the bucket.
This prevents over pressuring the pump (and risking water into cylinders), and being able to see the water going in means being assured it is.
Then I change to glycol last thing and suck that in before draining down for the winter.

 

[nimbusgb]

+1 - our yard is not particularly happy with people running engines ashore for this very reason, though I don't know if it's outright prohibited. I wasn't worried with Kindred Spirit because her long keel and bilge fins meant she couldn't really fall over whatever happened, but I'd be a bit more circumspect with a fin keeler on props and an older more bouncy engine.

Pete

-1 !!

Your yards need to sort out their cradling methods!

In Greece there are frequent earth tremors and infrequent ( thankfully ) earthquakes and boats rarely fall of cradles these days.

Running an engine should certainly not topple your boat!

 

[pheran]

-1 !!

Your yards need to sort out their cradling methods!

In Greece there are frequent earth tremors and infrequent ( thankfully ) earthquakes and boats rarely fall of cradles these days.

Running an engine should certainly not topple your boat!

Quite agree. After the incident I described, management insisted that if you were going to come out and over-winter ashore, you had to have proper purpose built yacht stands. As I said, it was some years ago and nothing untoward has happened since.