Willy Lewis

Brewer South Freeport Marine, ME

The injection pump on a diesel engine is great for pumping fuel, but when air gets into the fuel system—from changing fuel filters, for example—you have to bleed it out. Fill the primary fuel filters with clean diesel. You can also draw fuel into them using the hand pump, but that will take at least five minutes of pumping. Better to prime them. Find the bleeders, crack them open, use the hand pump until solid fuel comes out, and then close them. If the engine hasn’t been run dry, it will probably start. If the engine ran out of fuel, then on an old-fashioned diesel, you’ll have to bleed the injectors, too. Using an open-end wrench, crack the fuel supply lines at each injector about half a turn. Crank the engine, and tighten each fuel line when you see solid fuel. The engine should fire.

Bill Cripps

Mystic Shipyard, Mystic, CT

A common-rail diesel usually doesn’t need bleeding. You can often just crank it until it starts. But it’s easier, when you’re changing fuel filters or if the engine’s been run dry, to fill the primary filters from a container. Then, use the hand pump on the diesel engine to move the fuel into the secondary filter. This is a plunger-style pump: You simply unscrew the collar and pull out the plunger. Don’t open the secondary filter, but fill it by pumping. Once you feel firm pressure against the plunger, re-stow it and then start the engine. Any air left in the lines will be blown through. Never loosen a fuel line on a common-rail diesel; there’s enough pressure to take off some skin with fuel spraying out. If you do open a line, you have to throw it away and replace it with a new one. 

Don Young

Dutch Wharf Boat Yard, Branford, CT

You can get air in the lines in many ways: A valve can have a bad seal; O-rings can be worn; hoses can be in bad shape. If your engine stops, check the filters: They have to be chock-a-block full. If they’re not, you’ve got air. With older diesels, you had to get all the air out, but a common-rail engine, with its high fuel pressure, will almost bleed itself. You don’t have to crack the injectors open like on the older engines, and you shouldn’t; the fuel pressure is enough to cut you if the spray hits you. Don’t do anything beyond the secondary fuel filter, the one on the engine. Many engines have a bleed point on that filter; that’s as far as you should go. Crack the bleeder, use the hand lift pump to fill the filter until solid fuel comes out, and then close the bleeder and start the engine. 

This article originally appeared in the March 2020 issue.

Related

2666808_1500.30112018100014

Diesel fuel filters: Which should you choose?

If you want your diesel engine to run properly, you need the right fuel filters.

iStock-650347648_1800

Fill Her Up?

It used to be common to fill fuel tanks before storing your boat for the winter, but that was before ethanol-spiked gasoline.

2016-Carver-C50-anchor-1187_1800

Get Grounded

Two of the hardest-working pieces of gear on any boat are the anchor and windlass. With a bit of TLC, they’ll work reliably for years.

iStock-120672178_1800

Bottom Check

When your boat’s on the hard, use the opportunity to check below the waterline. Here’s what to look for.

DCC_3127_1800

Combat Corrosion

Modern outboards usually corrode before they wear out. Here’s how to prevent that from happening.

redrhino_9240922_1800

Maintaining Your Steering System

Steering systems are reliable, but these experts caution boat owners not to ignore them or you might lose your heading

38grandecoupe_interior_19_2602_1800

Keep it Cool

If you don’t want to sweat through the dog days of summer. it’s important to give your air conditioning some TLC to keep things chilly.

Viking68C-20_1800

The Benefits of Oil Analysis

Pros say oil analysis is like bloodwork for your engine, and you should get it done.