Diesel is hard to start.

[Cap]

One thing you can do to resolve any bleeding issues is to add a squeeze pump/bulb in line close to your fuel tank; the same kind used on outboard tanks. That way, anytime you open up the fuel system and let air in all you have to do is squeeze the pump until you hear fuel returning to the tank; of course the system has to be closed before doing this. At that point there should be no air in the system. I have these on my diesels and it makes life so much easier after changing filters, etc...

[Suijin]

Originally Posted by Raquin

I didnt even know it had glow plugs. My neighbor told me to turn the key for 20 sec but that didnt help. Where are the glow plugs. If each cyl has them I dont see them just injectors
Thank for the help

If it's running fine once it starts then I doubt it's a fuel delivery issue.

Where are you located and what is the temperature? Have you been running the engine for the past few months, and now it's getting colder and it won't start? If you didn't know you had glow plugs, then you probably didn't know that in colder weather it's going to require them being energized longer before you start trying to kick her over to start.

Not sure of your engine panel but on an Erickson with a Westerbeke I'm going to assume you have a key, a glow plug button, and a start button. Just turning the key won't energize the plugs unless you have a newer panel. Some panels with allow you to turn the engine over without the glow button depressed, and others don't. Just checking.

[Raquin]

Originally Posted by brankin

If the engine will start, the air is gone from the fuel lines. The glow plugs are about the size of a felt tip pen with a small stud on top with a wire attached. You will have one on each cylinder somewhere near the injectors. The reason your friend told you to hold the switch for 20 seconds was to activate the plugs but like most advice it was misguided. Holding it for 20 seconds, probably burned them up. As a rule of thumb on a marine diesel, 5 to 6 seconds is all you need. One test you can do is to blow hot air into the intake with a heat gun and have someone crank the engine. If this works, the glow plugs are burned out or the circuit is bad. If not, turn to compression.

You can buy a cheap compression tester at harbor freight and test the compression on each cylinder. Check the specs on your engine but it should be around 340 psi on each cylinder. If it is low, you might have stuck or bent valve(s) or a ring problem. If it is low, you might want to have a mechanic take over unless you a not afraid to tear into an engine.

Thanks so much. I am going to try the heat gun. I think you might have something here.

[twinboat]

Originally Posted by brankin

If the engine will start, the air is gone from the fuel lines. The glow plugs are about the size of a felt tip pen with a small stud on top with a wire attached. You will have one on each cylinder somewhere near the injectors. The reason your friend told you to hold the switch for 20 seconds was to activate the plugs but like most advice it was misguided. Holding it for 20 seconds, probably burned them up. As a rule of thumb on a marine diesel, 5 to 6 seconds is all you need. One test you can do is to blow hot air into the intake with a heat gun and have someone crank the engine. If this works, the glow plugs are burned out or the circuit is bad. If not, turn to compression.

You can buy a cheap compression tester at harbor freight and test the compression on each cylinder. Check the specs on your engine but it should be around 340 psi on each cylinder. If it is low, you might have stuck or bent valve(s) or a ring problem. If it is low, you might want to have a mechanic take over unless you a not afraid to tear into an engine.

I have been involved in diesels for 40 years. I have never heard of your rule of thumb about 2 seconds. My volvo TAMD40B manual states " preheat about 30 seconds". If I don`t preheat, 30 to 40 seconds, it don`t start.

[Stu Jackson]

You know what kind of engine you have. You didn't know if it had glow plugs. Go to Marine Diesel Engines and Engine Parts - Universal, Volvo, Westerbeke, Yanmar, MASE and find your engine and look around. If you don't have an engine manual, get one.

Many Westerbekes and Universal/Kubotas come with glow plugs, but the older ones don't have glow plug solenoids. Install a solenoid to significantly reduce the amount of time needed to hold on the glow plugs by avoiding long wiring runs all the way to the cockpit panel and back.

[bmm32005]

My starting instructions says hold the glow plug button for 20-30 seconds. I also the the volt meter drop a bit when I push the button. Leave your heat gun at home.

[Cheechako]

I've never had a diesel that started hard in cold weaather without the use of glow plugs. Perkins, Bukh, Yanmar and Volvo up here in the PNW and in wintertime. Unless you're in Alaska, I think you are looking at the wrong thing or your particular engine needs them for somereason....

[pbiJim]

30 seconds will not burn up a glow plug. Some modern engines actually keep the glow plugs going for a few minutes after the motor starts.

Most glow plugs will glow within about 10 seconds of seeing power, but that varies with the length & diameter of wire that feeds them as well as the condition of the battery bank. Diesels tend to have beefy starting batteries for two reasons. The extra load of the glow plugs is one of them. The high compression of the motor is the other. Glow plugs draw a lot of juice.

You can do a quick check on a glow plug with an ohm meter. Most should read just a few ohms from center post to ground when good. If you see variations greater than about 20% on the readings from plug to plug, then further investigation is probably a good idea. When my glow plugs fail, they usually fail as an open circuit.

I have only actually needed glow plugs during cold weather. 50F was cold enough to make a significant difference in starting time. 40F was cold enough to not start without glow plugs active on some motors I have used.

If you just messed with the fuel lines, then I would expect air in the lines is your most likely source of trouble. Sailor Chick's methods for dealing with that sort of thing are pretty close to the way that I would respond to that particular problem.

[twinboat]

Indirect or pre combustion chamber, diesel engines typicaly need preheat to start, even in warm weather. You can google "indirect diesel" for an explaination.

[brankin]

I have an Isuzu 3lb1 genset that was hard to start and i pulled all the glow plugs and found that two had burned out from holding them on to long. They do and will burn up depending on the impedance of the plug so it depends on your brand of plug. Mine is a pre combustion engine so it will not start without the plugs. I pulled the plugs and tested each one and they would glow red hot in 4-5 second so this is the right amount of time for my bosch plugs. Test your own and time how long it takes for them to get red hot and that is the amount of time for you engine ...period.

[Steve Bean]

Holding the glow plugs on 30 or so seconds will not "burn them out." They not only heat up themselves, they heat up the air in the chambers. In my old Mercedes the plugs have a resistance of about one-half ohm. (0.5 ohm). Much more means it's open, or burned out. Much less, it's shorted. They don't last forever. Measure the resistance between the tip of the plug, where the wire is attached, to the engine block. With the glow plugs " on" you should find around 11 volts DC between the tip of the plug and the block.

[brankin]

Originally Posted by Steve Bean

Holding the glow plugs on 30 or so seconds will not "burn them out." They not only heat up themselves, they heat up the air in the chambers. In my old Mercedes the plugs have a resistance of about one-half ohm. (0.5 ohm). Much more means it's open, or burned out. Much less, it's shorted. They don't last forever. Measure the resistance between the tip of the plug, where the wire is attached, to the engine block. With the glow plugs " on" you should find around 11 volts DC between the tip of the plug and the block.

I guess I didn't burn mine out...That was a figment of my imagination or maybe George Bush did it. Damn him because the engine only had 100 hrs on it.

[twinboat]

You most likely did have bad glow plugs, but saying they failed due to you holding them on longer then 3 or 4 seconds, goes against all engine builders preheat instructions.

[brankin]

Originally Posted by twinboat

You most likely did have bad glow plugs, but saying they failed due to you holding them on longer then 3 or 4 seconds, goes against all engine builders preheat instructions.

My manual states 2 sec at 68 deg, 3.5 sec at 32 deg and 5 sec at -15 deg F
I freely admit that I held my plugs for 20-30 seconds and burned them out. This is my experience with my Isuzu 3lb1 but you can perheat you engine for as long as you wish. Some plugs are designed for the operator who can't read a manual. It is not helpful to make blanket statement because each engine is different and someone could do damage to their engine taking advice that was contrary to what is in the engine manual

[DeepFrz]

Question 4
What causes glow plug failure and what are the results?

Answer
Excessive voltage is the leading cause of glow plug failure.
Glow plugs are designed to operate within a temperature range of 850° – 1100°C. During operation, the glow
plug controller switches current to the glow plug for a specific period of time to allow for proper heating.
However, when the controller fails, current could be applied for a longer than specified time causing the
temperature of the glow plug to exceed the 1100°C upper limit. Under these conditions, the glow plug overheats
causing the casing to swell, split or burst which allows air to enter the coil area causing immediate failure.

Other causes of glow plug failure include:
• Improper testing procedure (applying 12 volts directly to a glow plug designed to operate on 6 volts)
• Incorrect engine timing
• Improper fuel injector spray pattern
• Continual cycling of the glow plugs

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