Whatever is wrong, do not lose your head! If you are in deep water, set sails or drift. If you are in shallow water, deploy an anchor. If you are at the dock, roll up your sleeves! Diesel malfunctions fall under two general categories; while you are running the engine stops; the engine will not run or start. Diesel engines are so simple, they typically need only good fuel and enough turning speed with compression, to fire.
The Engine will Not Start or Run, You Hear no Starter Sound
- make sure power is turned on. (Do the lights come on?)
- make sure that the battery has power. (Are the lights on?)
- make sure you have power to the starter. (Try shorting across the starter solenoid)
- If you have no power to the starter, check the engine ground. If you have a working battery, you can use jumper cables to engage the starter. R and R starter, take to automotive shop to bench test starter.
The Engine Turns Over Slowly or the Starter Makes a Clicking Sound
- Make sure that you have enough battery power. Turn on a light and see how dim it gets when you engage the starter, a light that nearly goes out means that you do not have near enough battery power.
- Check all you connections from battery to engine. Faulty grounds are the leading cause, check the ground circuit.
- If the battery is fully charged and you get a clicking sound from the starter, you most likely have a faulty solenoid on the starter.
- A trick that may help you get started with a near dead or low battery is to use the decompression lever on the diesel engine. Engage the decompression lever, have someone else turn the engine with the starter, release the lever when the engine is turning fast enough. Of course you could always crank start your engine, I have seen diesels to 120Hp have crank starts.
The Engine Turns Over with Plenty of Power but Fails to Fire
- Make sure that you have enough fuel. (Check your tank, then the filters)
- Make sure that you have clean fuel. (Bleed, bleed, bleed. no water, no air)
- Go bleed the system again, bleed all fittings from lowest to highest, under pressure.
- If you feel confident in having completed the above tasks then check your filters for algae and extreme contamination. Change filters, lead main fuel line into five gallons of clean fuel. On a rare occasion something may have broken internally in the engine but this is very unlikely in an engine that has been just sitting.
- Much more terrifying for most people is when...
Your Engine was Running but has Now Stopped, the Engine Stopped Suddenly, in Less than a Second
- Do not try a restart yet, you do not want to cause permanent damage if you have not already.
- Make sure that you prop is not fouled. Look over the side. try putting the transmission in neutral and turn the shaft from inside the boat.
- Make sure that you did not cook your engine. Turn the key to run and look at the temperature gauge. Does your engine smell hot?
- Make sure that you did not have a major engine failure. Try to turn the engine with the hand crank to make sure that it moves freely.
- This is truly a rare event for an engine to just stop suddenly. If your engine turns freely by hand, then you may try the starter. If you hear and noise at all, stop turning the engine.
The Engine Stops Slowly, Perhaps with a Little Surging
- Make sure that you did not turn off the key or throttle. Try a restart as you normally would.
- Make sure that you have not overheated. Turn over the engine and make sure that you have water coming out of the exhaust.
- Make sure that you have clean fuel. The number one cause of diesel problems is this. Bleed your fuel, then again, then again.
- The past is a good indicator for this one. Surging in the past with occasional shutdowns is an indicator that you need to bleed your fuel system of either air (likely) or water (sometimes). Did you do any work on the engine recently? Check to see that all is right. Often what was touched last (or moved because of a repair) is where I look. You may have rapped on a stretchy nylon or poly line on the propeller and it took a bit for it to stop the engine, check over the side. An internal engine failure is not to be ruled out but is very rare (I had a valve pushrod break one time and the engine just wound down).
Other Stuff that Goes Wrong, X File
No Water Out of the Exhaust, the Engine is Running Hot
- Make sure that the water pump is hooked up. (did a belt come off or is it slipping?)
- Make sure that the system is not clogged; this will also ensure that the pump is indeed working. Shut off the through hull intake to the engine. Remove intake hose from through hull and place in a bucket of water. If water flies out of the exhaust when you test start it this way, you more than likely have a plugged through hull, often a plastic bag! If you get only a trickle of water out of the exhaust then a: r and r your impeller, if it persists b: flush 2 gallons of vinegar into your raw water system and let it sit for 20 minutes - this trick has saved many boat owners from the expense of a slowly clogging saltwater cooling system.
- Check all your hose connections, maybe you are now pumping raw water into your bilge! Rare, weird things include collapsed hoses and sheared impeller spindles. Check your through hull filter if you have one, vegetation and even fish can clog them.
