How long do you run the engine each time?

[sighmoon]

If you're going to start the engine, is it best to run it for an hour or so, to get everything up to temperature and oil coated, or just the minimum to get from the marina entrance to the berth?

I'm not so worried about the effect on the battery, as we'd be plugging in at the marina anyway.

 

[Lucky Duck]

Depends.....

 

[Tranona]

If you're going to start the engine, is it best to run it for an hour or so, to get everything up to temperature and oil coated, or just the minimum to get from the marina entrance to the berth?

I'm not so worried about the effect on the battery, as we'd be plugging in at the marina anyway.

Major cause of short life of yacht engines is lack of use. Engines will typically run 8000 hours if run properly. This means getting up to temperature and running at between 2/3 and full power. So worst thing to do with them is run for short periods at low revs then switch off. Run at least 30 minutes under load, preferably an hour. When motoring or motorsailing keep revs up - on modern engines at least 2000 and run at higher revs from time to time.

 

[CAPTAIN FANTASTIC]

Do don't idle the engine for too long; start it like if it was a car; then rev up and go.

 

[RupertW]

Do don't idle the engine for too long; start it like if it was a car; then rev up and go.

+1

I wouldn't worry too much about the engine battery if the engine starts fine - if you are likely to need the domestic battery fully charged for a night sail or whatever then use marina power if you have enough time beforehand, or just accept you'll need to use the engine at decent revs for an hour during the day.

I know the theory about idling but as I often have to run the engine in idle for an hour at anchor if staying for more than one night, I would have thought the harm would have been done by now - I'm at 12000 engine hours so far.

 

[johnalison]

Do don't idle the engine for too long; start it like if it was a car; then rev up and go.

Not so easy if you are negotiating the Dutch canals or entering the locks at Brunsbuttel, when prolonged idling is forced on you. I can do no more than hope that good periods of hard motoring help to undo the harm.

 

[ChiPete]

To warm up from cold, I'll run our Yanmar 3YM20 in neutral at 1200 rpm for 8-10 mins. This is about 500 revs above idle and the practice was recommended by a Yanmar engineer.

On return, because of the low revs required to enter the marina and make our way to the berth she has a chance to cool down. Finally when we're on our berth, I'll leave her at idle for 3-4 mins.

 

[johnalison]

+1

I wouldn't worry too much about the engine battery if the engine starts fine - if you are likely to need the domestic battery fully charged for a night sail or whatever then use marina power if you have enough time beforehand, or just accept you'll need to use the engine at decent revs for an hour during the day.

I know the theory about idling but as I often have to run the engine in idle for an hour at anchor if staying for more than one night, I would have thought the harm would have been done by now - I'm at 12000 engine hours so far.

I don't get much charge until 1400 rpm and use this on the rare occasions when I need to charge. If I am just running the engine, I run it at 2000 rpm in gear.

 

[Lucky Duck]

To warm up from cold, I'll run our Yanmar 3YM20 in neutral at 1200 rpm for 8-10 mins. This is about 500 revs above idle and the practice was recommended by a Yanmar engineer.

On return, because of the low revs required to enter the marina and make our way to the berth she has a chance to cool down. Finally when we're on our berth, I'll leave her at idle for 3-4 mins.

I'm glad I am not berthed next to you!

10 minutes at high revs sounds like an inordinate amount of time and similarly my understanding was that cooling down only really applied to those with turbo chargers?

 

[KellysEye]

>Run at least 30 minutes under load, preferably an hour. When motoring or motorsailing keep revs up - on modern engines at least 2000 and run at higher revs from time to time.

Agree, the worst thing to do is run an engine at low revs.

 

[sighmoon]

I'm glad I am not berthed next to you!

10 minutes at high revs sounds like an inordinate amount of time and similarly my understanding was that cooling down only really applied to those with turbo chargers?

I'd never heard that before, and our engine has a turbo charger (which makes it sound faster than it is).

 

[maby]

I don't think that running for a short period is any worse for the engine than running the engine unnecessarily for half an hour to get it fully warmed up - though it is undoubtedly bad for the oil and will require more frequent oil changes.

It is certainly the case that the first five or ten minutes after starting from cold puts far more wear onto the engine than the next several hours, but the period of running after the engine has warmed up is not going to undo that wear. If you can't avoid starting the engine, then I just don't see that running it unnecessarily for half an hour is going to make much difference.

 

[Lucky Duck]

I'd never heard that before, and our engine has a turbo charger (which makes it sound faster than it is).

The bearings on the turbo charger should be allowed to cool before the engine is switched off although I would have thought the run into the marina would be sufficient to do that. Same with car engines.

 

[maby]

I'd never heard that before, and our engine has a turbo charger (which makes it sound faster than it is).

You should give any turbo-charged engine a few minutes at low speed to let the turbo cool before you switch it off. The interior of a turbocharger gets very hot and if it is allowed to come to a complete stop before it has cooled, it can do a lot of harm to the oil that is in it.

 

[TQA]

Mine gets run for the shortest time possible. The best moment of the day is when the donk goes quiet and peace reigns with the sails pulling us a long. BLISS

If you do lots of short runs and rarely get the OIL up to full working temp then change the oil frequently say twice a year regardless of engine hours.

 

[johnalison]

The instructions on my non-turbo Volvo 2030 say that I should idle for 15 mins from hot to allow it to cool. As someone says, this is often effectively done while manoeuvring into a harbour/mooring. the only time I feel concerned is in the middle of a long motor at sea, when I might want to stop the engine to check something such as the water filter. When changing from motor to sail, I normally idle for as long as I can bear it, which is a few minutes.

 

[Blueboatman]

Can't add much except that if it hasn't been used for a while I spin it decompressed until the oil alarm goes silent . Then do a normal start. This ASSUMES you are not filling the exhaust full with water ( i have a hirise exhaust) risking HYDROLOCKING . (Prob worth stressing).
Other than that, 2- 3 min warm up then load on .

 

[Searush]

I start mine just before I start to cast off & then go. Try to get at least 20 mins running before putting sails up & stopping it. I hate running it to charge the batteries on the quayside, I prefer to just potter up & down the harbour a couple of times & say "Hi" to the neighbours if I need a charge & I am not going out into the Strait.

 

[stuartwineberg]

Keep it loaded

I don't think it has been explicity stated here but the magic phrase is "under load" - it ain't good practice to run up the engine to temperature without being in gear.

 

[tidclacy]

Is not the rule of thumb start diesel engine and go, idle before switching off and the opposite for a petrol engine?