# Diesel Starting - Glow Plugs



## Siamese (May 9, 2007)

What's the procedure for diesel engine starting if equipped with glow plugs? In particular, my Yanmar 3YM20.

Always use on cold starts?
How long to run them before cranking?


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## Rockter (Sep 11, 2006)

I have never liked glow-plug starting systems.
Give me direct injection any day.
.


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## MarkSF (Feb 21, 2011)

Rockter said:


> I have never liked glow-plug starting systems.
> Give me direct injection any day.
> .


Both direct and indirect-injection engines have glow-plugs. Whether we like them is beside the point, the engine won't start (or is very hard to start) cold without them.

To the OP, the answer is however long it takes to start the engine easily. For a really cold start, it might be 40s. I usually give it 30s unless it's really cold. However, that's on my 1984 Universal. The manual states 30s to 1 minute.

The Yanmar manual says 15s.

http://www.yanmaritalia.it/amministrazione/repository/varianti/mo_pdf/8/YM_V2_21JAN09.pdf

Is there some reason you don't want to just follow the instructions?

Modern engines have quicker-heating glow plugs. Modern TDI cars take 2s.

Bear in mind that time on the glow plugs is saving work that the starter motor would do. So if you suspect that the battery charge is marginal, it's really important to give the glow plugs the full time.


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## klem (Oct 16, 2009)

The only thing that I would add to what MarkSF said is that you do not want to exceed the engine manufacturer's recommendation for length of time by too much. The reason for this is that some glow plug tips will break off and fall into the cylinder if left on for way too long. I have never heard of this happening from someone holding them on too long but it does occasionally happen on engines with an automatic controller that fails and leaves them on. This is really not something to worry about, just don't run them for 5 minutes. Yes, you should absolutely be using them though, they are there for a reason.


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## bljones (Oct 13, 2008)

You shouldn't need more than 30 s on a glow plug for the engine to happily start. If you do, the water's likely too hard to sail on anyway.
If the manuals says 15 s, I'd use 15 s.


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## eherlihy (Jan 2, 2007)

BL, Mark and klem have it right...

The only thing that I would add is that on many engines, the starter will not crank unless the Glow Plug button is pushed as well as the starter button. 

I usually push the glow plug button for about 20s, then push the start, and I am rewarded with a happily purring engine.


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## eherlihy (Jan 2, 2007)

... also one man's 15s, may be my 20s. This ain't Swiss timing or anything. When the engine is cold, I just count 1- one thousand, 2 - one thousand, 3 - one thousand... 20 - one thousand, and push the start button, while still holding the glow plug button.


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## dabnis (Jul 29, 2007)

I had a VW Diesel which had an automatic time out device, IIRC about no more than 10 seconds or so. In really cold weather it wasn't enough so I installed a solenoid operated by a switch to power the the plugs for as long as I wanted to. I can't remember ever glowing for more than about 20 seconds or so. Suggest you try a little, if no fire go another 10 or so, assuming everything is up to spec, such as compression & so on.

Paul T


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## Stu Jackson (Jul 28, 2001)

rtfm is always good advice. 

Universal diesels (I know, you don't have one) have glow plugs. The older model engines ran the (small) wiring from the batteries all the way to the cockpit panel and then back to the glow plugs. This required the 30 second warm up. Many of us have installed solenoids for the glow plug circuit which reduces the time to 15 seconds or less.

The newer Universal engines have a built in solenoid.

The newer Universals also have a (strange-to-me) start circuit wiring arrangement where the glow plugs are tied into the fuel pump and oil pressure switch requiring you to hold the glow plugs on to bleed the engine! Although the newer engines are self bleeding, it is rather a PITA. CRITICAL UPGRADES - DO THESE OR ELSE!!!

That said, the advice is to simply do what the manual tells you to do and then to completely understand how YOUR engine and wiring works. Beware PO changes, too.

In many cases, having the glow plugs ON at the same time you push the starter button or key switch will create difficulties because of the large electrical draw on the batteries. On our boat, I do the glow plugs, release them, then start.

Hard starting is usually related to bad electrical ground connections at the engine.


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## sailor1950 (Dec 8, 2009)

I don't see a glow plug circuit on may engine panel. almost automotive diesels have a glow plug indicator. some engine panels have another stop on the key circuit. I dont see either on my panel. Maybe some 3ym20's don't have them .?


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## William E. Heritage (May 1, 2005)

Recently I went to start my 3 cyl diesel. It had been about two weeks since last started and I was concerned that I might not have enough juice to turn her over. I always have a hard time starting my diesel when it's on the cool side. Sooooo I just rolled the engine over a time or two and determined I had plenty of electricity in the batteries. Then I held the glow plug button in for my normal time then the starter. It started up faster than ever. Normally I hold the glow plug button in for 20 - 30 seconds then the starter and it grinds and grinds usually starting. I believe that in the past I have been heating an empty cylinder. By cranking it first it allowed fuel to enter the cylinders to be heated.


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## H and E (Sep 11, 2011)

I have an older (1988) Universal that starts well in the summer with about 5 to 10 seconds of glow plug. I run the electric fuel pump first for a few seconds then the glow plug then the starter and she fires right off. I only use the glow plugs first time for the day after that it starts quickly without them. In winter with air temp in the 50's I run the glow plugs a little longer. Haven't sailed in colder weather yet.


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## Oaksail (Jan 6, 2011)

MarkSF said:


> Both direct and indirect-injection engines have glow-plugs. Whether we like them is beside the point, the engine won't start (or is very hard to start) cold without them.
> 
> My direct injection Volvo Penta 2002 does not have glow plugs. Takes a little extra cranking in the cold but otherwise starts right up.


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## Mark1948 (Jun 19, 2007)

I have a 3ym20 and there is nothing in the manual about glow plugs, I was also told they did not use them. I did read in the manual to put the throttle full on to start and cut back as the engine revs. Makes a big difference in starting.


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## Zanshin (Aug 27, 2006)

Oaksail;955105...My direct injection Volvo Penta 2002 [U said:


> does not[/U] have glow plugs. Takes a little extra cranking in the cold but otherwise starts right up...


Which engine do you have - I went to Volvo Penta's page and chose 2 marine engines at random and both have glow plugs.


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## Oaksail (Jan 6, 2011)

Hi Zanshin,

2002 is the model number. 2 cylinder
2003 is the 3 cylinder


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## Oaksail (Jan 6, 2011)

Zanshin said:


> Which engine do you have - I went to Volvo Penta's page and chose 2 marine engines at random and both have glow plugs.


Hi Zanshin,
i found the document, link below

http://www.bottrell.ca/images/Volvo2002BrochureA41987.pdf


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## Zanshin (Aug 27, 2006)

Oaksail - I looked at the shop manual for the D1-20 engine (the 2002 2-Cyl 18HP one that I think you have) and it shows me where the 2 glow plugs are installed on page 46.

Manual : http://www.maritimsd.no/Customers/msm/documents/Dokumentasjon Volvo/D1.pdf


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## Maine Sail (Jan 6, 2003)

Zanshin said:


> Oaksail - I looked at the shop manual for the D1-20 engine (the 2002 2-Cyl 18HP one that I think you have) and it shows me where the 2 glow plugs are installed on page 46.
> 
> Manual : http://www.maritimsd.no/Customers/msm/documents/Dokumentasjon Volvo/D1.pdf


D1-20 is different from the 2002. The Model 2002 does not have glow plugs..


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## Oaksail (Jan 6, 2011)

Maine Sail said:


> D1-20 is different from the 2002. The Model 2002 does not have glow plugs..


Thanks Maine Sail,

I just discovered too during an injector cleaning that this Volvo model with copper injector sleeves does not use copper washers to seal the gap between the injector and cylinder head.


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## WInsome. (Dec 10, 2011)

A tip that I was recently given that works very well . . .if you have a heat gun or blow dryer, blow heated air into the air intake and see how much easier it will start.


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## Charlie Knupp (Oct 13, 2015)

I have a Northern Lights 5KW diesel that has a start and glow plug button; I always had to hold glow plug for at least 15 sec before engine would start; now I find that pushing glow plug and start at same time, engine starts immediately; is this indicative of a problem ? The reason I ask, the other day, I went to start the engine by holding the glow plug button and start - nothing, no clik, no start no nothing; I tapped the starter with a hammer ( that worked a long time ago) nothing, did it again and it started; I did check the batteries and connections and connection to starter beforehand and they were good. Answer ?? Also, the owner manual talks about checking the glow plugs. I have 3200 hours on this generator.


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