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allanbranch · 03-11-2015, 12:49

Okay total diesel newbie here, prepare yourself for a silly question.

Just bought a project boat that has a yanmer diesel motor, my first diesel. When I bought it the PO fired it right up. Now I can't get it to fire. If this was a gas engine I would squirt some starter spray in it for now to fire it and later clean the carb. But I'm a total newbie at diesel.

What is my troubleshooting line of thought here?
Test the choke to see if it's hooked up? How would I do that?
How do I know if I've over-choked it? Can I flood a diesel?

Sorry about all these silly questions, I appreciate your wisdom.

**sailorchic34** · 03-11-2015, 12:54

There is no choke on a diesel. Move the throttle to about 1/2 open and crank it. Once it fires, push the throttle back to idle and let it warm up for 5 minutes.

If it does not fire, search this forum for how to bleed a diesel engine. A rite of passage.

Enjoy.

allanbranch · 03-11-2015, 14:50

I will try again tomorrow and start googling "bleed a diesel engine."

Thanks for your help.

dohenyboy · 03-11-2015, 15:15

Diesels are different than gas engines is that they do not stop when you turn off the key. They will continue to run without electricity. Ok there are a few models that will stop. If there is no electricity, a solenoid shuts off the fuel. But on most diesels, including my 1980 Toyota jeep, you have to pull a stop lever or push a stop button.
If your is the lever type, make sure it is pushed back in or your engine will never start. Don't ask how I know.

Why can't things remain where i carelessly left them?

DeepFrz · 03-11-2015, 15:44

As you have been cranking the engine without it starting make sure that your exhaust system is drained of water and that the water intake sea cock is closed. You wont flood a diesel with fuel but you can flood it with sea water and that could be a disaster. Open the sea cock as soon as it starts. If the engine wont turn over you may have water locked it.

Ensure the fuel cut off is open and if you have glo plugs use them for 10 to 20 seconds before cranking the engine. The previous owner may have warmed up the engine before you got there so it would make it easier to start.

Make sure the start battery is well charged and the engine is spinning well.

Its not recommended for routine use but many here have used starter spray to start their engines.

Good luck.

**a64pilot** · 03-11-2015, 16:12

I'm betting fuel shut off, is off. Easy thing to miss, especially if Diesel's not your thing.
On edit, do older Yanmars have fuel shut off's or solenoids?

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Cheechako · 03-11-2015, 16:26

-Make sure any fuel valve is open.
-Do not crank more than maybe 15 seconds at a time (your starter cable may melt!)
-If you crank too much without starting, you may fill your exhaust with water and end up flooding salt water into the cylinders!
-Some boats have a drain on the muffler to get the water out, many don't.
- You can shut the seacock (water inlet valve) to t he engine to avoid this flooding while you try to get the engine to start. Be sure to open it immediately upon starting.
-As mentioned, check for any cable handle near the engine controls, often a T handle or a knob. It should be in to start the engine and out to stop the engine.

**sailorchic34** · 03-11-2015, 16:44

Quote:

Originally Posted by a64pilot

I'm betting fuel shut off, is off. Easy thing to miss, especially if Diesel's not your thing.
On edit, do older Yanmars have fuel shut off's or solenoids?

Sent from my iPad using Cruisers Sailing Forum

Older yanmars gm series and older are all manual pull the stop cable. And yes if it's pulled, the engine will not start at all....

Boatyarddog · 03-11-2015, 17:13

So here's a tip you almost never hear.
Be very cautious when cranking any wet exhaust engine for longer than a minute without it starting.

The reason is that the engine exhaust is required to purge the water lift muffler of its water, without the engine starting it's Very possible to pump enough water into the muffler that it will back up into the engine and cause a hydro lock condition and possibly bend rods or damage the engine.

So if it does not start within a minute of cranking or even less, either shut the raw water ThruHull off, or disconnect the raw water pump belt until it does start, this will not damage the pumping system, and will possibly save you a ton of headaches later.

Sent from my iPad SV Cloud Duster

Boatyarddog · 03-11-2015, 17:15

Quote:

Originally Posted by Cheechako

-Make sure any fuel valve is open.
-Do not crank more than maybe 15 seconds at a time (your starter cable may melt!)
-If you crank too much without starting, you may fill your exhaust with water and end up flooding salt water into the cylinders!
-Some boats have a drain on the muffler to get the water out, many don't.
- You can shut the seacock (water inlet valve) to t he engine to avoid this flooding while you try to get the engine to start. Be sure to open it immediately upon starting.
-As mentioned, check for any cable handle near the engine controls, often a T handle or a knob. It should be in to start the engine and out to stop the engine.

Sorry didn't see this before I chimed in.
BUT ITS MOST IMPORTANT.

Sent from my iPad SV Cloud Duster

Rhapsody-NS27 · 03-11-2015, 17:21

I'd say bleed the lines. Mine wouldn't start for a while so I bled the lines. I also cleaned fuel filter housings and changed out filters. Took a little cranking but it fired up again.

**StuM** · 03-11-2015, 18:06

Quote:

Originally Posted by a64pilot

I'm betting fuel shut off, is off. Easy thing to miss, especially if Diesel's not your thing.
On edit, do older Yanmars have fuel shut off's or solenoids?

Or decompression lever - depending on model.

gamayun · 03-11-2015, 20:22

You should Google your model # and try to download the manual for future reference. You might also find it helpful to order Troubleshooting Marine Diesels by Peter Compton. There're probably others recommended if you were to search this forum.

I'm with the others on this: close the seacock until you get it started, then open this right away and make sure you have water flowing out the boat's exhaust hose. Check the fuel shut off. Mine is a knob inside the cockpit locker, way away from the engine key. I'd never have known it was there if I had not been paying attention to the broker when she shut off the engine. Mine gets stuck in the "shut-off mode," which is in a pulled-up position, so I have to make sure it's pushed in completely after cutting fuel to the engine before it will start again. You do know that the key only starts the engine and the fuel shut off starves the engine of fuel...right? I push the throttle almost to max and then back it off as soon as it fires. You don't want to rev it at high RPM when it first starts. If that doesn't work, bleed all the appropriate points and check your fuel and air filters. You do have fuel in the tank....right?

According to Mack Borings, the recommended procedures to get the engine oil circulated before starting the engine is to: 1) Hold the stop button (fuel shut off) and crank the engine for 5 sec. 2) Stop and wait 10-15 sec. 3) Hold stop button and crank engine for 5 sec. 4) Release stop button and start engine. This process is even more important if the engine has a turbo charger, which I don't have so can't be of any help there.

If you've been cranking it a lot, you might also want to check and make sure there's no salt water in the engine. Get it out as quickly as you can, if you did this, and follow recommended procedures on what to do to get it back in working order.

Have fun!