Maintenance Tip of the Week: White Smoke 12/14/2015

Maintenance Tip of the Week – White Smoke 12/14/2015

Smoke is always a leading indicator of engine problems, normally fuel or combustion related. With the current emissions standards that require compliance from Marinediesel, you should never see smoke coming from your exhaust. That said, what does white smoke indicate?

1. Bad fuel quality (most common)

2. Problems with combustion

As to bad fuel quality, the first step should be to check the filtration and see what is causing the problem. Fuel treatment or enhanced filtration may solve the issue.

Regarding combustion, there are many causes: Pump failure, air filtration or exhaust pressure issue, clogged injectors, changes made to the ECU, worn gaskets or damaged manifolds.

If the fuel quality is good, then the presence of white smoke indicates that major service is absolutely necessary.

Marine Maintenance and Diesel Engines



Maintenance of diesel engines is directly tied to life cycle and reliability. Modern marine engines are proven to perform well over long periods of time, provided that regular routine maintenance is performed.

One factor that is often neglected is the harshness of the marine environment. Salt is corrosive. Humidity causes corrosion. Fuel quality can vary greatly from one place to another. These issues help explain why most marine diesel engines have a much shorter time between overhauls than a similar engine that is installed on a truck or other type of vehicle.

Engine ratings also have a bearing in longevity. Engines that are rated for recreational use, for instance, are designed to be used in a recreational application. Use one of these engines in a heavy commercial setting, and problems are certain to ensue. Maintenance costs will certainly multiply exponentially. At MarineDiesel, we see this situation quite frequently. A potential customer will ask us for a quote on a commercial vessel, but they choose a cheaper engine that was rated for recreational use. Will the engine function? Certainly. Will the boat explode? Certainly not. However, the maintenance expense will be much higher, the life cycle will be much shorter, and the vessel performance will be lacking.

Is it still a good deal…?

All engines require periodic maintenance. As a manufacturer, we are in the “Front Lines” regarding maintenance issues. We see patterns as to what issues occur, not only in our engines, but in engines manufactured by competitors. The three most common maintenance issues that we see are often avoidable, and if diligently monitored, can greatly extend the service life of a marine engine (of any brand):

  1. Fuel quality: The number one (by far) problem we see is the use of bad fuel and neglected filter and polishing.
  2. Exhaust temperature: This is probably the number two issue. The biggest leading indicator of required maintenance.
  3. Smoke: Smoke tells you a lot, from a diagnostic perspective. It is nearly always an indication of required maintenance.

Though a bit of a cliche, engineers often state over and over again, “Read the manual”. The maintenance schedules we develop and publish are based on extensive testing results and are updated based on customer feedback, experiences, and warranty returns. In other words, the schedules are not simply made up out of thin air. If we recommend filter changes every 100 hours, there is absolutely a reason.

Bottom line: If maintenance and service schedules are followed, your engine will give you a far longer service life, and cost you far less money over the long term.



Green Engine Regulations and Development



Whether you agree with the premise of climate change or not, tighter emissions controls are coming, and engine users around the world will soon be forced to ensure that their engines are in compliance with new, stricter emissions regulations. These regulations impact not only the marine market, but all industrial, on road vehicles, and off road vehicles.

The next batch of regulations coming for the marine industry will come into effect in 2016, with further reductions coming in 2020.

On this blog, we have published the following resources for your reference, that we hope you find useful.

Emissions Page

Links Page

Yes, the regulations are complex. Yes, they can be confusing. In general, the following organizations make and enforce the regulations:

  • IMO (Global Shipping)
  • EU (Europe)
  • EPA (USA)
  • CARB (California)

Though there is quite a lot of overlap in the limits, the IMO has tried to at least make the rules somewhat consistent. The specific regulation regarding maritime emissions is known as MARPOL Annex VI.

Generally, there are a number of Emissions Control Areas (ECAs) that govern the maximum amount of emissions that may be emitted. The current ECAs are:

  • North America, including all of the USA, all of Canada, and large parts of the Caribbean
  • Most of Europe (Stricter regulations in areas like Bodensee)
  • The Black Sea
  • The Arctic (Separate treaty)
  • The Antarctic (Separate treaty)

ECA Boundaries

seca map

Additionally, engines are classed based on the tier of environmental regulations with which they comply. All MarineDiesel VGT engines have tested for Tier IV and are awaiting certificate issuance in 2014. Current Tier IV regulations are listed HERE.

If your vessel will operate in any of the ECAs, your engines must be in compliance.

The following emissions are covered under the regulations:

CO2 (Carbon Dioxide)

NOx (Nitrogen Oxide)

PM (Particulate Matter)

CO (Carbon Monoxide)

Smoke (as a percentage of emissions)

The above list of emissions are products of combustion. They can be removed or reduced through engineering, aftermarket treatment options, or a combination of methods. All MarineDiesel VGT engines are in compliance with the above (no after treatment required). Additional regulations apply to:

SOx (Sulphur Oxide)

SOx is a product of the fuel used. All diesel fuel has some level of SOx present. The use of Ultra Low Sulphur Diesel (ULSD) can control SOx emissions.

All of these regulations are controversial to one extent or another, in particular SOx regulations.


The answer is cost. ULSD is over twice the cost of lower grades of diesel (Due to more refining, politics, and other reasons), and since vessel operations have fuel as their biggest operating expense, by far, this has a huge impact on operating costs. In fact, within the ECAs, lower grades of fuel than ULSD are increasingly unavailable.

Our posting tomorrow will address your options if you own a non-compliant, older engine.






Ask Professor Diesel 05/05/2014 – Smoke


This week’s question comes from Paul in China

Professor Diesel:

What causes excessive smoke? We seem to be getting more smoke recently than we normally get from running your engines.



Quantities of diesel smoke are often due to incomplete combustion, normally as a result of faulty or dirty fuel injection. Improper mix of fuel to air is the reason why you will see smoke, particularly on engines that have been used for a while.  A small amount of exhaust smoke is normal during initial start-up or rapid acceleration.

Black smoke is normally the result of incorrect timing, bad fuel, or incorrect engine compression.

White smoke could indicate faulty glow plugs, incorrect compression or timing, or as a result of condensation in cold climates.

Blue smoke should be of immediate concern, as it indicates worn piston rings, leaking oil, or scored cylinder walls.

What is important to remember is that, though a small amount of smoke is perfectly normal, excessive amounts of smoke are indicators of required maintenance and must be addressed as soon as possible.


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