I just read an article in "latitude 38" about diesel maintenance which recommended running regularly for several minutes to help eliminate water in the fuel and stated that these engines love to idle. I have read from other sources that diesels should not be idled more than is absolutely necessary and should be run only under load whenever possible. Which is correct???? Or is this one of those never ending debates like synthetic versus fossil oil?
Diesel Ops
- Thread starter gfrazzle
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Lat 38 is wrong
don't idle your engine any longer than necessary, diesels love to run under load.
don't idle your engine any longer than necessary, diesels love to run under load.
Run it under load at the dock...
You can run your engine under load at the dock. Keep your dock lines attached and put the engine in gear. Run it up to about 2000 rpms and let it run for 15-20 mins. We do this during the winter months as needed.
You can run your engine under load at the dock. Keep your dock lines attached and put the engine in gear. Run it up to about 2000 rpms and let it run for 15-20 mins. We do this during the winter months as needed.
With my propellor I would hesitate to run
that hard while tied to the dock. I fear that I could break something. Some of you have bigger engines than I and putting fifteen horsepower into your dock lines, cleats and hard points on the dock seems a bit risky.
that hard while tied to the dock. I fear that I could break something. Some of you have bigger engines than I and putting fifteen horsepower into your dock lines, cleats and hard points on the dock seems a bit risky.
The issue is oiling...
there are many components inside of an engine, not all have their own pressurized lubrication, things like timing chains and cylinder walls are "splash" lubricated. With the low volume of oil being pumped around at idle, these things aren't getting much "splashing", but at the same time they aren't moving very fast. I've never head of a warmed up, broken in diesel engine suffering internal damage at idle, but it's safe to say it doesn't hurt anything to rev it up a little bit for some extra lubrication if it's going to be sitting in neutral for a while, for example when charging batteries. Just be careful not to shift it into gear! On another note, (not really boat related), those new audi le mans racecars with diesel engines essentially get an extra gear in their transmissions than their gasoline counterparts, because while a high-performance racing gas engine may stall below 1800 rpm (or higher!), the Audis can go below 500 without stalling, and that lets them use a 1st gear equivalent to the gas engine's second gear!
there are many components inside of an engine, not all have their own pressurized lubrication, things like timing chains and cylinder walls are "splash" lubricated. With the low volume of oil being pumped around at idle, these things aren't getting much "splashing", but at the same time they aren't moving very fast. I've never head of a warmed up, broken in diesel engine suffering internal damage at idle, but it's safe to say it doesn't hurt anything to rev it up a little bit for some extra lubrication if it's going to be sitting in neutral for a while, for example when charging batteries. Just be careful not to shift it into gear! On another note, (not really boat related), those new audi le mans racecars with diesel engines essentially get an extra gear in their transmissions than their gasoline counterparts, because while a high-performance racing gas engine may stall below 1800 rpm (or higher!), the Audis can go below 500 without stalling, and that lets them use a 1st gear equivalent to the gas engine's second gear!
Moderation!!!!
Probably long idleing is hard on a diesel just as is too much of a load. One thing about idleing is that it allows the engine to cool down so that temperatures are more equal among the parts. I always idle for 5 minutes or so to allow an easy cool down. Shutting off a hot engine is asking for trouble. If I can't use my boat I start the engine at least once every two weeks. I usually put it into gear at lower RPMs forward and reverse. As Ross noted you must be wise about not putting too much strain on the docklines etc. My Volvo manual recommends a fogging of the engine if it isn't used at least once every two weeks. My diesel doesn't get very hot at idle without a load. I also figure that it does the transmission some good to get used a little.
Probably long idleing is hard on a diesel just as is too much of a load. One thing about idleing is that it allows the engine to cool down so that temperatures are more equal among the parts. I always idle for 5 minutes or so to allow an easy cool down. Shutting off a hot engine is asking for trouble. If I can't use my boat I start the engine at least once every two weeks. I usually put it into gear at lower RPMs forward and reverse. As Ross noted you must be wise about not putting too much strain on the docklines etc. My Volvo manual recommends a fogging of the engine if it isn't used at least once every two weeks. My diesel doesn't get very hot at idle without a load. I also figure that it does the transmission some good to get used a little.
Yanmar Disrtibutor Said....
....do not let idle for long periods. If necessary, kick it up to 1000 RPM +/ Don't use the engine for recharging on the mooring. However, given that most people do, limit it and then after leaving the mooring, run it WOT for about fifteen minutes after you get her up and running to clean her up. For charging batteries on the mooring, run it about 1800 RPM. I believe this applies to the more modern, lightweight high RPM diesels and not the 1800 RPM variety. I think he also mentioned that 'warming it up at the dock' is not a good idea. Better to wait until you can get it under load. At least I think I recall this altho my notes are long gone. BTW, in my newish marina, I have to take care to run the engine for a while both ways (in and out) long enough to get it warmed up and under a good load. My slip is close to the entrance and it's easy to be underway sailing long before the engine is warm. Rick D.
....do not let idle for long periods. If necessary, kick it up to 1000 RPM +/ Don't use the engine for recharging on the mooring. However, given that most people do, limit it and then after leaving the mooring, run it WOT for about fifteen minutes after you get her up and running to clean her up. For charging batteries on the mooring, run it about 1800 RPM. I believe this applies to the more modern, lightweight high RPM diesels and not the 1800 RPM variety. I think he also mentioned that 'warming it up at the dock' is not a good idea. Better to wait until you can get it under load. At least I think I recall this altho my notes are long gone. BTW, in my newish marina, I have to take care to run the engine for a while both ways (in and out) long enough to get it warmed up and under a good load. My slip is close to the entrance and it's easy to be underway sailing long before the engine is warm. Rick D.
Diesel class
I took a diesel class from Chris Oliver in Annapolis a couple of years ago and his recommendation was to start it and leave. No need to warm it up, you're just wasting fuel and polluting the air. If it won't run w/o being warmed up then you probably have other problems. As for charging the batteries on the hook, Ok to run it for anywhere from 1 to 2 hrs at 1000 rpms w/o fear of glazing the cylinder walls. In regards to running it in gear at the dock Autoprop had me do it fwd and rev to verify the prop was correctly pitched. Made me a little nervous when powering towards the dock but it held without a problem. I crank her up every now and then after doing some maintenance and while I keep a hand on the throttle, the lines and cleats seem to be more than capable of handling the load. I've seen more stress and been more worried during some of the storms that have passed through then when running the engine in gear. If you don't think she'll hold due to engine power then I would question if she'll hold during a bad storm.
I took a diesel class from Chris Oliver in Annapolis a couple of years ago and his recommendation was to start it and leave. No need to warm it up, you're just wasting fuel and polluting the air. If it won't run w/o being warmed up then you probably have other problems. As for charging the batteries on the hook, Ok to run it for anywhere from 1 to 2 hrs at 1000 rpms w/o fear of glazing the cylinder walls. In regards to running it in gear at the dock Autoprop had me do it fwd and rev to verify the prop was correctly pitched. Made me a little nervous when powering towards the dock but it held without a problem. I crank her up every now and then after doing some maintenance and while I keep a hand on the throttle, the lines and cleats seem to be more than capable of handling the load. I've seen more stress and been more worried during some of the storms that have passed through then when running the engine in gear. If you don't think she'll hold due to engine power then I would question if she'll hold during a bad storm.
Yes the cleats at dockside and boat hardware
should easily hold the boat with engine running under load. I regularly raise my sails to hose them down while tied at the dock confident the boat is not going to go anywhere. A spring line and engine in gear will hold a boat tight to the dock to facilitate boarding or loading while being just one line away from taking off. As far as warming engine up I believe it is best done underway gradually increasing RPMs. A 5 minute cool down period before shutting the engine down I believe is most important. Personally I do not like the practice of running the engine just to charge batteries. It think its a waste of fuel and engine life. I rather enter a marina and use shorepower + (shower and restaurant) or use a portable generator on the hook. A worn out generator or battery charger can easily be replaced.
should easily hold the boat with engine running under load. I regularly raise my sails to hose them down while tied at the dock confident the boat is not going to go anywhere. A spring line and engine in gear will hold a boat tight to the dock to facilitate boarding or loading while being just one line away from taking off. As far as warming engine up I believe it is best done underway gradually increasing RPMs. A 5 minute cool down period before shutting the engine down I believe is most important. Personally I do not like the practice of running the engine just to charge batteries. It think its a waste of fuel and engine life. I rather enter a marina and use shorepower + (shower and restaurant) or use a portable generator on the hook. A worn out generator or battery charger can easily be replaced.
Has anyone here considered using vegetable oil
as fuel. I told a friend about it and he bought an old Mercedes and for $730 had it converted to run on vegetable oil. He gets his oil for free from a neighborhood fast food chicken place. The diesel was originally designed to run on peanut oil. With the price of gas and diesel going out of sight I will be replacing my F250 with a diesel truck. Just food for thought and possibly your boat. Frank
as fuel. I told a friend about it and he bought an old Mercedes and for $730 had it converted to run on vegetable oil. He gets his oil for free from a neighborhood fast food chicken place. The diesel was originally designed to run on peanut oil. With the price of gas and diesel going out of sight I will be replacing my F250 with a diesel truck. Just food for thought and possibly your boat. Frank
Water in Fuel
Getting back to the original question......... Most diesel experts advise against prolonged idling in view of the detrimental effects on the engine itself. However; if water in the fuel is a problem, especially in winter, running the engine for awhile will allow the primary fuel filter to capture some of the water in the fuel. Since most of the fuel will go back into the fuel tank the fuel will run through the filter several times--also known as "polishing" the fuel. While I personally think this practise may eliminate some of the water in the fuel, it would be better to diagnose the source of the problem and eliminate it. Also, especially in winter (at least in the coller parts of the country) it is better to keep the fuel tank completely filled to eliminate the air space that allows water to condense. So if your run your engine you may be extracting some water, but the increase air space will allow additional condensation, and it may not be great for the engine.
Getting back to the original question......... Most diesel experts advise against prolonged idling in view of the detrimental effects on the engine itself. However; if water in the fuel is a problem, especially in winter, running the engine for awhile will allow the primary fuel filter to capture some of the water in the fuel. Since most of the fuel will go back into the fuel tank the fuel will run through the filter several times--also known as "polishing" the fuel. While I personally think this practise may eliminate some of the water in the fuel, it would be better to diagnose the source of the problem and eliminate it. Also, especially in winter (at least in the coller parts of the country) it is better to keep the fuel tank completely filled to eliminate the air space that allows water to condense. So if your run your engine you may be extracting some water, but the increase air space will allow additional condensation, and it may not be great for the engine.
Vegetable Oil from restaurants ....
Be careful with such oil as they may contain a lot of oleic acid (the decomposition of animal fats, etc.) and oleic will requite that you change most of the seals and gaskets in the system. Oleic is not compatible with normal neoprene, buna, and requires teflonic (expensive) etc. seals and gaskets for long term service.
Be careful with such oil as they may contain a lot of oleic acid (the decomposition of animal fats, etc.) and oleic will requite that you change most of the seals and gaskets in the system. Oleic is not compatible with normal neoprene, buna, and requires teflonic (expensive) etc. seals and gaskets for long term service.
Why idling is ill advised
Diesels need to run hard to keep the exhaust from building up in the mixing elbow, which eventually will clog the thing entirely and shut down the engine.
Diesels need to run hard to keep the exhaust from building up in the mixing elbow, which eventually will clog the thing entirely and shut down the engine.
Run It Hard
I have a diesel truck as well as a diesel in my boat. I have been advised by mechanics for both to run them hard, they love to work. In fact the boat guy said that every month I should pretend my sailboat is a power boat...take it out and run it at 75% WOT for an hour.
I have a diesel truck as well as a diesel in my boat. I have been advised by mechanics for both to run them hard, they love to work. In fact the boat guy said that every month I should pretend my sailboat is a power boat...take it out and run it at 75% WOT for an hour.
How about 100% full throttle
If I am not mistaken, my Yanmar manual suggests running at full power periodically. I think it suggest 10% of the time that the engine is run. I've done it a few times for about ten minutes with a close eye on the temperature gauge.
If I am not mistaken, my Yanmar manual suggests running at full power periodically. I think it suggest 10% of the time that the engine is run. I've done it a few times for about ten minutes with a close eye on the temperature gauge.
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