My twin Volvo D4 engines are nearing 10 yrs in age; however have very low operating hours (less than 200) I routinely run the engines on a monthly basis. . . get them up to temps, check all systems, etc. Sometimes I cruise at no wake speed around a few miles and sometimes just run them in neutral at the dock. . . idle then up to 1000-1500 rpm and back for 1/2 hour or so. My fuel tanks are nearly full and the last top off was more than a year ago. I used a biocide at the fill up. Lately I am getting blue smoke more than ever before. I am inclined to take it out to open waters and give it a good Italian tune up. . . max throttles for a while. And/or should I visit the local marina for a fuel polishing exercise. Opinions please.
Diesel engines/exhaust/fuel question
- Thread starter ccdjoe
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"My twin Volvo D4 engines are nearing 10 yrs in age; however have very low operating hours (less than 200) I routinely run the engines on a monthly basis. . . get them up to temps, check all systems, etc. Sometimes I cruise at no wake speed around a few miles and sometimes just run them in neutral at the dock. . . idle then up to 1000-1500 rpm and back for 1/2 hour or so. My fuel tanks are nearly full and the last top off was more than a year ago. I used a biocide at the fill up. Lately I am getting blue smoke more than ever before. I am inclined to take it out to open waters and give it a good Italian tune up. . . max throttles for a while. And/or should I visit the local marina for a fuel polishing exercise. Opinions please."
Low load and idling at the dock will always tend to produce blue smoke as lube oil sneaks past every seal and ring before the engines reach temp and see loads. Generally speaking it is best to avoid just idling at the dock or starting up and idling for long periods as it takes a long time to reach temps and serves no real purpose. Assuming your engines can reach WOT in gear +3-5% as a brief test you will find that running them at normal cruising speeds on plane will clean out just about all of the residual oil and much of the carbon. Extended idling with no loads and/or full time operation at very low loads only will eventually set up a condition that requires a more robust cleaning method.
Hope this helps
Low load and idling at the dock will always tend to produce blue smoke as lube oil sneaks past every seal and ring before the engines reach temp and see loads. Generally speaking it is best to avoid just idling at the dock or starting up and idling for long periods as it takes a long time to reach temps and serves no real purpose. Assuming your engines can reach WOT in gear +3-5% as a brief test you will find that running them at normal cruising speeds on plane will clean out just about all of the residual oil and much of the carbon. Extended idling with no loads and/or full time operation at very low loads only will eventually set up a condition that requires a more robust cleaning method.
Hope this helps
In addition to what Charlie and smitty said your engines may not be really broken in and need to be run under load to properly seat piston rings. You are not doing them any favor by extended idling.
When I couldn't use my boat for extended period I just started them briefly every few months until oil pressure was up then shut down
When I couldn't use my boat for extended period I just started them briefly every few months until oil pressure was up then shut down
"OK, here's my question on the subject...
I've also always heard it was not good to run diesels for extended time under low or no load conditions. So why do truckers often let their engines idle, sometimes hours at a time?"
I have two observations to contribute to this question.....
1. On most all of the trucks the amount of time spent idling is very small compared to the time they are under load. Most which you see do this DO NOT OWN THE TRUCK and instead are driving a company rig so they have less invested in the outcome.
2. With all due respect as well as the fact that this will not apply to all truckers let me say that an average truck driver (not owner) it not necessarily the best example to use for "best diesel practices".
If you want to get some much more in depth and detailed responses to this question I suggest you post this over at boatdiesel(dot)com. Within a short period of time a number of Volvo owners and diesel engine enthusiasts will supply their view of this.
Hope this helps
I've also always heard it was not good to run diesels for extended time under low or no load conditions. So why do truckers often let their engines idle, sometimes hours at a time?"
I have two observations to contribute to this question.....
1. On most all of the trucks the amount of time spent idling is very small compared to the time they are under load. Most which you see do this DO NOT OWN THE TRUCK and instead are driving a company rig so they have less invested in the outcome.
2. With all due respect as well as the fact that this will not apply to all truckers let me say that an average truck driver (not owner) it not necessarily the best example to use for "best diesel practices".
If you want to get some much more in depth and detailed responses to this question I suggest you post this over at boatdiesel(dot)com. Within a short period of time a number of Volvo owners and diesel engine enthusiasts will supply their view of this.
Hope this helps
I have been cranking up and letting them run at idle for a only few minutes before placing them in neutral and advancing them to 1000 to 1500 rpm for about 20 min, then back to idle for a minute or so before shutting down. They sync up and purr during that time while getting up to matching temp, pressure, etc. I have to travel about 5 miles to get out of no wake and that has prevented me from going out in the sound where I can open them up. . . however, I think I have to do this more often. . . will check it out.
On the other hand do y'all think the fuel being 2 yrs old, even with biocide, could be the main problem? What is your opinion of "fuel polishing". . . how do you deal with old fuel? Tanks hold over 200 gal.
On the other hand do y'all think the fuel being 2 yrs old, even with biocide, could be the main problem? What is your opinion of "fuel polishing". . . how do you deal with old fuel? Tanks hold over 200 gal.
"I have been cranking up and letting them run at idle for a only few minutes before placing them in neutral and advancing them to 1000 to 1500 rpm for about 20 min, then back to idle for a minute or so before shutting down. They sync up and purr during that time while getting up to matching temp, pressure, etc. I have to travel about 5 miles to get out of no wake and that has prevented me from going out in the sound where I can open them up. . . however, I think I have to do this more often. . . will check it out.
On the other hand do y'all think the fuel being 2 yrs old, even with biocide, could be the main problem? What is your opinion of "fuel polishing". . . how do you deal with old fuel? Tanks hold over 200 gal."
Adding rpms to a diesel at idle does almost nothing to assist in reducing cold engine oil passing and carbon buildup. A good practice is to start your engines when you need to use the boat and let them idle for very few minutes before heading out at harbor speeds. When your temp gages show reasonable temps for a couple of minutes somewhere near normally operating temps it is fine to put the boat on plane then.
Biocide should not be used unless you have a specific tank problem and only then in careful doses so you do not have fuel pump or injector problems.
Fuel problems are normally first identified by swift increases in the vacuum gages on your fuel filters or if you do not have them very premature plugging of those filters.
I you are not experiencing premature plugging of filters or a rapid rise in vac gage readings then there is no reason to even consider fuel polishing.
As I posted above the slight blue smoke is most probably lube oil not fuel oil that is leaking back to the cylinders due to low loads and idle time which are perfect ingredients to allow this to happen.
If you have full tanks that are 2 years old and you did not condition/stabilize the fuel back then it is still likely fine but long periods like these will begin to affect diesel fuel.
"Too old fuel" that is not contaminated by water or other solvents is often pumped out of the tanks and utilized in home heating burners mixed about 50/50 with new heating oil.
Perhaps adding engine pre-heaters to the engine pans will help in your engine warm-ups if that is a problem in your harbor.
Only run the engines when you need them, do not idle and run at 5 mph or less for no reason, run the engines up to speed when you get a chance, do not treat fuel with biocides for no reason, do add fuel conditioner to very old fuel(Stanadyne, Valvetec or some other well regarded additive), do consider polishing fuel but only if you have a known fuel problem.
These symptoms appear to all revolve around engines which are not used enough and when they do get started they hardly ever see a load- that is the primary enemy to your engines right now.
Hope this helps
On the other hand do y'all think the fuel being 2 yrs old, even with biocide, could be the main problem? What is your opinion of "fuel polishing". . . how do you deal with old fuel? Tanks hold over 200 gal."
Adding rpms to a diesel at idle does almost nothing to assist in reducing cold engine oil passing and carbon buildup. A good practice is to start your engines when you need to use the boat and let them idle for very few minutes before heading out at harbor speeds. When your temp gages show reasonable temps for a couple of minutes somewhere near normally operating temps it is fine to put the boat on plane then.
Biocide should not be used unless you have a specific tank problem and only then in careful doses so you do not have fuel pump or injector problems.
Fuel problems are normally first identified by swift increases in the vacuum gages on your fuel filters or if you do not have them very premature plugging of those filters.
I you are not experiencing premature plugging of filters or a rapid rise in vac gage readings then there is no reason to even consider fuel polishing.
As I posted above the slight blue smoke is most probably lube oil not fuel oil that is leaking back to the cylinders due to low loads and idle time which are perfect ingredients to allow this to happen.
If you have full tanks that are 2 years old and you did not condition/stabilize the fuel back then it is still likely fine but long periods like these will begin to affect diesel fuel.
"Too old fuel" that is not contaminated by water or other solvents is often pumped out of the tanks and utilized in home heating burners mixed about 50/50 with new heating oil.
Perhaps adding engine pre-heaters to the engine pans will help in your engine warm-ups if that is a problem in your harbor.
Only run the engines when you need them, do not idle and run at 5 mph or less for no reason, run the engines up to speed when you get a chance, do not treat fuel with biocides for no reason, do add fuel conditioner to very old fuel(Stanadyne, Valvetec or some other well regarded additive), do consider polishing fuel but only if you have a known fuel problem.
These symptoms appear to all revolve around engines which are not used enough and when they do get started they hardly ever see a load- that is the primary enemy to your engines right now.
Hope this helps
Capt. Bill1
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You need to start to take the boat out and run it or sell it. The longer you keep doing what you're doing the worse it is for the engine/s.
As others have said, the blue smoke is oil smoke. And as others have said, it's more than likely because the rings have not/are not seated well.
You don't need your fuel polished, you need to use it.
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I really don't get this. Why not run thru the NWZ at idle and then put a load on the engines? By the time you reach the end of the NWZ your engines will be at the perfect temp
Running them in neutral at higher rpm really doesn't accomplish anything as there is still no load on them
Blue smoke is oil, sounds like stuck rings from lack of use. I agree with the other responses, polishing will not do anything unless your tanks are dirty and your filters clog up
If taking the boat out requires such an effort you never do, then sell the thing
Running them in neutral at higher rpm really doesn't accomplish anything as there is still no load on them
Blue smoke is oil, sounds like stuck rings from lack of use. I agree with the other responses, polishing will not do anything unless your tanks are dirty and your filters clog up
If taking the boat out requires such an effort you never do, then sell the thing
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The most important thing as many have said is o go out and run the boat on plane. This gets the engine to full operating pressures and temps.
But I want to clarify a few points. One reason it is essential to run the engines at say 40% load or more is that the rings seat due to the explosion pressure in the cylinders. The pressure blows against the rig lands and forces the rings to seat on the cylinder wall. At very low or no loads, the rings aren't properly pressurized and the cylinders can glaze. This can permanently damage the cylinder walls and lead to performance and smoking issues. Obviously loading the engine also blows out the turbos, carbon buildup etc.
I also believe it is fine and considered a good practice to run the engines unloaded to operating temp for 15 or 20 minutes every two or four weeks if the boat is not going to be used. The caveat though is that assumes the engines are routinely run at proper loading. In this case the unloaded running keeps surfaces lubricated throughout the engine and ancillary components and prevents corrosion. No glazing or carbon buildup will occur if the engines are ordinarily run under load.
As said above it is also a good practice to warm the engines for 5 minutes and then head out at near idle speeds until engines are at full operating temps, then get up on plane.
But I want to clarify a few points. One reason it is essential to run the engines at say 40% load or more is that the rings seat due to the explosion pressure in the cylinders. The pressure blows against the rig lands and forces the rings to seat on the cylinder wall. At very low or no loads, the rings aren't properly pressurized and the cylinders can glaze. This can permanently damage the cylinder walls and lead to performance and smoking issues. Obviously loading the engine also blows out the turbos, carbon buildup etc.
I also believe it is fine and considered a good practice to run the engines unloaded to operating temp for 15 or 20 minutes every two or four weeks if the boat is not going to be used. The caveat though is that assumes the engines are routinely run at proper loading. In this case the unloaded running keeps surfaces lubricated throughout the engine and ancillary components and prevents corrosion. No glazing or carbon buildup will occur if the engines are ordinarily run under load.
As said above it is also a good practice to warm the engines for 5 minutes and then head out at near idle speeds until engines are at full operating temps, then get up on plane.
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As far as biocides go, I don't agree with the comment above. Using a biocide like biobore adds some lubricity to the fuel, good for injectors and pump. My personal practice is that if the boat is going to sit for a while or nor be refueled then a low dose of biobore is a good idea. Also if you get fuel from any questionable source, it is much easier to use biobore as a preventative treatment before you have growth. Once you have growth then using the biocide makes a mess as it kills the growth and clogs the filters.
The goal is to never allow growth to start and I don't see a down side to limited use of a preventative biocide and always trying to use fresh clean fuel.
The goal is to never allow growth to start and I don't see a down side to limited use of a preventative biocide and always trying to use fresh clean fuel.
What Rick (silver lining) said about the rings seating when there is more load on the engine is exactly correct. Especially about the cylinder walls glazing is break-in is not done properly. If the cylinders glaze, the rings may NEVER seat and the engine will smoke all it's life.
Look at GVP's engine break-in procedure.
http://www.boatered.com/forum/topic.asp?TOPIC_ID=51384
He used to recommend a 50 hr break-in procedure but now has a 20 hrs break-in period. The main purpose of the break-in is the seating and mating of wear surfaces. The first break-in is for the flat tappet cam...2000RPM for 20 min. Then it's the rings.
I still use his 50 hrs break-in procedure of which I am right in the middle of now.
Look at GVP's engine break-in procedure.
http://www.boatered.com/forum/topic.asp?TOPIC_ID=51384
He used to recommend a 50 hr break-in procedure but now has a 20 hrs break-in period. The main purpose of the break-in is the seating and mating of wear surfaces. The first break-in is for the flat tappet cam...2000RPM for 20 min. Then it's the rings.
I still use his 50 hrs break-in procedure of which I am right in the middle of now.
Old fuel and/or contaminated fuel general info.....
- Most typically any dark or solid contaminants in these fuels are not microbes but instead are asphaltenes which are byproducts of age or poor refining.
- Microbes will only exist when there is a water/fuel interface in the tanks and therefore water is a key ingredient to avoid
- Water in tanks can easily be tested for with a stick wiped in a water paste indicator most often through the fuel gage sender area.
- When water and or a water/fuel interface is detected in the tank it is close to the bottom and can often be mostly 'decanted' off with fuel pump and length of soft copper pipe (ie - ice maker line)
- Killing microbe growth with a biocide will often generate a larger solids and slime problem that filters and separators will have a tough time dealing with, be ready for this.
- Constant use of biocides can affectively make the microbes 'immune' to that particular biocide leaving further treatments much less effective.
- Biocides function with ingredients like halogens (chlorine, fluorine etc), Boron or similar chemical compounds all of which will allow free electrons often associated with increased metal corrosion at high tolerance areas such as injector tips and fuel injection pumps.
All of us should avoid water in the tanks as a primary action and do whatever we think is best for our engines in our specific situations.
Hope this helps
- Most typically any dark or solid contaminants in these fuels are not microbes but instead are asphaltenes which are byproducts of age or poor refining.
- Microbes will only exist when there is a water/fuel interface in the tanks and therefore water is a key ingredient to avoid
- Water in tanks can easily be tested for with a stick wiped in a water paste indicator most often through the fuel gage sender area.
- When water and or a water/fuel interface is detected in the tank it is close to the bottom and can often be mostly 'decanted' off with fuel pump and length of soft copper pipe (ie - ice maker line)
- Killing microbe growth with a biocide will often generate a larger solids and slime problem that filters and separators will have a tough time dealing with, be ready for this.
- Constant use of biocides can affectively make the microbes 'immune' to that particular biocide leaving further treatments much less effective.
- Biocides function with ingredients like halogens (chlorine, fluorine etc), Boron or similar chemical compounds all of which will allow free electrons often associated with increased metal corrosion at high tolerance areas such as injector tips and fuel injection pumps.
All of us should avoid water in the tanks as a primary action and do whatever we think is best for our engines in our specific situations.
Hope this helps
I sure miss GVP. He was an extraordinary teacher..
His mention of cross hatching is consistent with what I always learned about gas engines. Strangely many diesel people think lack of cross hatching is a sign of a worn out engine. I just don't understand that idea.
His mention of cross hatching is consistent with what I always learned about gas engines. Strangely many diesel people think lack of cross hatching is a sign of a worn out engine. I just don't understand that idea.
I'm not a diesel guy...yet.. but would think if the fuel is over a year old ( & perhaps some of it a lot older?) there might be some possibility the cetane rating has degraded a little. So, while running it under decent load should help, it might not be wise to run max throttle as you suggest until you have a tank of mostly new fresh diesel.