Feb 13, 2020

Typical Diesel Fuel Systemsa typical diesel fuel system

Since the late 19th century, a debate has raged on the relative merits of diesel fuel over gasoline. In more recent decades, that argument has included boat manufacturers, and increasingly, individual boaters. As I pass through boat yards in the spring or fall, I’m sure to hear a comment or two (sometimes ruefully, other times with great joy) of the merit of a particular engine or fuel source.

Increasingly, diesel engines are praised for their long-life, ease of maintenance, compact design, reliability and safety, and rate of combustion. As well as cruisers and trawlers, many sailboat manufacturers in particular have chosen to install diesel engines. Volvo, Westerbeke, and Universal diesel engines are highly popular in North America.

At their core, the combustion cycle of a diesel engine is very similar to gasoline. The main difference is the way in which the fuel is burned. In a gasoline engine, a spark plug creates a spark, which ignites the fuel at the right time in the engine sequence. Diesel fuel doesn’t burn the same way: it relies on compression – the fuel is injected into the cylinders at the moment that air in the cylinders has been compressed, causing it to heat up and ignite the injected fuel. The fuel itself is quite different to gasoline, and boat owners should be aware that the maintenance of diesel fuel and associated parts are specific to diesel engines.

Many parts of the engine have to act in concert to allow this process to happen, and there are a number of maintenance items that a boat owner can take to aid in function and long-life of a diesel system.

Racor Style Fuel Filtera Racor-style fuel filter - a very common type of primary fuel filter

Here’s how it all works: Diesel fuel is stored in a fuel tank, onboard. A fuel transfer pump draws fuel from the tank to a primary fuel filter. This filter will separate any water in the fuel, and will capture any debris. Water removal is an important factor in the operation and longevity of the engine: water can corrode injectors, and can also create an environment where microbes flourish in the fuel itself.

The fuel transfer pump (which may be mechanical or electric) then pushes the fuel through one or more secondary fuel filters, to an injection pump. As a part of the fuel lines allowing the fuel to move, a fuel bleeding system allows a constant fuel flow to be free of any air.

A second pump, called a fuel injection pump, pushes the fuel (under high pressure) from a manifold, through each fuel line to each cylinder’s injector. The injector’s tip has very fine holes in it, which injects the fuel as a fine mist into the cylinder.

The fuel delivery system will use two different types of fuel lines: one type for the low pressure (for the fuel running from the tank, through the filters to the injection pump), and a second type for high pressure (for the fuel running through the lines to each injector).

Sta Bil Diesel BiocideBecause the fuel running to the injectors is under such high pressure, caution needs to be taken when working on/around a diesel engine. Any part of the body exposed to a leak in a high-pressure fuel line can cause high-pressure injection injury – where the pressure of the fuel is so high that it will break the skin and severely damage tissue.

Proper maintenance is the key to long-life and smooth operation in a diesel system. Here are a few items to watch for and to include in your maintenance schedule:

Glow plugs – glow plugs are small electrical devices the sit next to each cylinder and aid in the warming of the cylinder and air in the engine, prior to fuel being delivered. By pre-heating the cylinder, it makes starting much easier, especially on cold days. Glow plugs are arranged in a simple electrical circuit and should be tested to confirm their functionality, periodically.

Bleeding – Any air in the fuel lines needs to be ‘bled’ from the system, or the engine will be difficult to start and/or cause runability issues. Air gets into the lines in a variety of ways:

a) Running out of fuel

b) A loose fuel line, sucking in outside air

c) An improperly seated fuel filter or gasket

The bleeding process for an given engine is spelled out in the engines service manual, but it essentially involves a few steps: Addressing the cause of the air entry, loosening the bleed screw on the fuel line manifold and then engaging the fuel transfer pump to push fuel to the manifold. As the fuel arrives at the bleed screw, some will leak out, along with air bubbles. Continue bleeding the air bubbles until only fresh fuel escapes. Tighten the bleed screw.

Fuel filters – fuel filters remove both water and debris, both of which can cause major problems. Fuel filters should be replaced, per engine manufacturer’s directions, and any water separating fuel filters should be drained of water regularly

Fuel Polishing – diesel fuel doesn’t break down the same way that gasoline does, and tends to be more optimal for long-term storage. However, diesel is susceptible to microorganism/bacterial growth within the fuel – and water/debris are major obstacles to proper engine function. Fuel polishing is the process by which diesel fuel is cleaned of microorganisms, water and micro-debris. There are a number of systems available on the market as add-on kits to an engine, and fuel polishing is also a service offered by a number of marine repair facilities.

Winterizing – If fuel polishing isn’t desirable, adding a biocide to the fuel tank is an essential part of winterizing. There are a number of different products and brands available, and they are designed to chemically inhibit microorganism growth in the fuel.

Andrew McDonaldAndrew McDonald is the owner of Lakeside Marine Services – a boat repair/maintenance firm based in Toronto. Andrew has worked in the marine industry for 12 years and is a graduate of the Georgian College ‘Mechanical Techniques - Marine Engine Mechanic’ program.

Questions or comments for Andrew? Email him directly via: This email address is being protected from spambots. You need JavaScript enabled to view it.

Related Articles
Maintenance
  • 10 June 2020
  • By Ethan

Ask Andrew – Pump it up

Boats contain several pumps, each serving a unique purpose and positioned in a way that allows it to do its job effectively. Understanding the why and the how can be important in troubleshooting when an...

Maintenance
  • 28 May 2020
  • By Ethan

Cored Deck Repair

It’s race night and the breeze is strong. Sails are full, the rigging is taught and the crew are working hard. Footfalls hit the deck and bodies move across the cabintop. The boat is tacked and...

Lifestyle

  • Prev
Classic boat restoration expert and wooden boat builder Stan Hunter recently sent us this great ...
In Mid June, a floatplane plunged into Constance Bay on the Ottawa River after two planes collide ...
Winter is a fun time for sailmakers in Canada. We grind through mountains of repairs and have an ...
The seasoned sailor mapped out an ambitious course around the world — aboard his 28-foot ...
Clean wake: A concept amongst cruising sailors that stresses the impact that individual behaviour ...
This line-up of Beneteaus can to us from our friends at RCR Yachts in NY State where they are ...
As another harsh Victoria winter came to a close, the deck repair and refinishing continued with ...
The Peterborough Canoe Company was formed in 1892 and began production the following year after ...
On one of the sunny days we had recently, Kyle MacTaggart in Honey Harbour ON fired up the Merc to ...
For all those OnBoard subscribers who have followed along with the maintenance, repairs and ...

Cobourg Yacht Club - 2015 Sailing instructorsKatherine Stone

Like many other harbours on Lake Ontario, Cobourg has seen its fair share of changes. Screams used to be heard from kids piled into a toboggan on wheels that went hurtling down a wooden slide into the harbour. Above it all was the bustling din from the waterfront of ship’s whistles, train engines, foghorns and thundering coal cars. It is now a rather serene place for the locals and visitors to enjoy various watercraft. Fortunately, the beautiful beach that lines the waterfront is still a star attraction for the town.

Located 95 kilometres east of Toronto and 62 kilometres east of Oshawa on the north edge of Lake Ontario, United Empire Loyalists first starting arriving in the area as early as the 1780s. The first settlement in 1798 was called Buckville, later renamed Amherst, then called Hamilton (after the township) and also nicknamed Hardscrabble. It wasn’t until 1819 that they finally settled on the name of Cobourg, which was incorporated as a town in 1837. In the late 1820s large schooners with passengers and cargo had to anchor well off shore, as there was only a landing wharf. A group of Toronto businessmen formed the Cobourg Harbour Company which built the wooden Eastern Pier from tolls charged for the use of the harbour.

Read more: Cobourg Yacht Club...

Boat Reviews

  • Prev
New at the end of 2019, the 58 Salon Express design features large windows to flood the living ...
No wonder this is one of Regal’s best-selling boats; the Regal 33 Express offers amazing ...
The newest member of Beneteau’s Gran Turismo line is the GT 36 and this yacht brings the style and ...
With a philosophy of quality and 'doing things right Ranger Tugs launches the all new R-25 at the ...
The new Beneteau Swift Trawler 41 renews the spirit of the practical seaworthy cruiser. The ...
The Canadian Yachting test crew last week had the opportunity to run the Bavaria S36 HT at St ...

CY Virtual Video Boat Tours

Virtual Boat ToursWe all love boats and nothing can break us up! So, what better way to spend our time than looking at interesting boats and going aboard in a virtual ride or tour. We have asked our friends at various dealers and manufacturers to help us assemble a one-stop online resource to experience some of the most interesting boats on the market today. Where the CY Team has done a review, we connect you to that expert viewpoint. Our Virtual Show will continue to grow so visit frequently and check it out. If you can’t go boating, you can almost experience the thrill via your screen. Not quite the same, but we hope you enjoy our fine tour collection.

 

Read more about the CY Virtual Boat Tours....................

 

Beneteau Oceanis 30.1As boat builders clamber to create ever-bigger platforms for ever-more generous budgets, the entry-level cruiser has become an elusive animal. Sure, if you want to daysail, there are plenty of small open boats from which to choose, but if you want a freshly built pocket cruiser, you’re in for a long search. Enter French builder Groupe Beneteau, which identified this gap in the market and set about creating the Oceanis 30.1, an adorable little cruiser that resembles her larger siblings in all but length and price. With all she offers, it wouldn’t be a stretch to call her a mini yacht.

Read More about the Beneteau Oceanis 30.1..................

Destinations

  • Prev
On May 19, the New York State Canal Corporation today announced an updated opening schedule for the ...
If you have four hours to enjoy a fine tour of one of Canada’s most interesting waterways (let’s ...
Boom & Batten Restaurant is suspended over the water adjacent to the Songhees Walkway and ...
Provincial Boat Havens are those special places to drop anchor in British Columbia’s West Coast and ...
NW Explorations, a Bellingham, Washington-based yacht charter, brokerage, and marine services ...

KingstonBy Amy Hogue

Cruise into the city of Kingston, Ontario, and it will quickly become clear that this city and surrounding waterways have something special. Built around the northern shore of Lake Ontario, Kingston is the place to go if you love to explore new waterways, fantastic views, and exceptional boating opportunities.

Sitting at the intersection of three world-class Canadian bodies of water, Lake Ontario, the St. Lawrence River, and the UNESCO World Heritage Site, the Rideau Canal (Cataraqui River from Kingston to Newboro), the water’s influence is deeply woven into Kingston’s culture and history. 

Read more about Kingston...........

 

Marine Products

  • Prev
Wet decking can compromise passenger safety on boats, particularly when boarding or disembarking. ...
Anyone who has repeatedly used a rag to clean gelcoat, paint and delicate surfaces has seen the ...
The new Mercury Racing 300hp Five‑Blade CNC Cleaver propellers are designed expressly to maximize ...
Beneteau may have outdone itself with introduction of its new Gran Turismo 36, manufactured in ...
Yanmar Power Technology has announced the development of a hydrogen fuel cell system for maritime ...
Kevin Monahan is a retired Canadian Coast Guard officer with more than 20 years of experience ...
The new 2020 PORTS Georgian Bay, North Channel & Lake Huron Guide is available for purchase at ...
Professional boatbuilders don't want to have to redo a job any more than a DIYer. Many choose Life ...
Since its introduction last year, the JBL by Harman Marine BassPro 10" Powered Subwoofer (JBLMBP10) ...
After decades of perusing charts and guidebooks as part of planning a cruise, it was a totally ...