Trouble Starting Diesel

[26ft_bathtub]

I have a Yanmar YSM8 inboard on the Bathtub that has done a sterling job to date.

However, the last few times I've run it, it has had a bit of trouble starting. Until recently, it started first time after about two or three seconds on the button. Now it takes two or three goes and much longer on the starter. Restarting after it's warmed up is easier.

It's still 70°F most days here, so it's not cold, but it's exhibiting similar characteristics to cold starting.

Now, the manual gives me about twenty different possible complaints, including the nebulous 'faulty starter', but I was hoping for a bit of input from you lot so I can start narrowing it down.

Anyone have any ideas about the most likely cause?

 

[ccscott49]

Jeeze could be a multitude of things, dirty injector, dirty fuel, lack of compression, heaters not working (if it has any) lots of factors. I'd check the heaters first. Will it start easily with easy start?

 

[pvb]

One possible cause...

One possible cause might be that air is leaking in to the fuel line slowly. When you try to start the engine after the boat has been left for a time, the fuel pump has to pump the air through before the engine will start. With a slow leak, air wouldn't get in quickly enough to cause poor starting while the engine's still warm. Have you disturbed any of the fuel line recently? Maybe changed a fuel filter? If it is a leak, it can be a difficult one to solve - took me a couple of days when it happened to my engine.

 

[Rabbie]

Help may be found here - http://www.freeboards.net/index.php?mfor...amp;showforum=2

 

[26ft_bathtub]

Re: One possible cause...

Don't know Easy Start--probably don't have that brand over here. It's some kind of fuel spray, right?

 

[hlb]

Re: One possible cause...

It's ether like stuff, you spray into the air filter. I'd get the injectors checked if easy start works.

 

[FWB]

This guy is having similar problems I think.

 

[Freebee]

Re: One possible cause...

what ever you do not resort to easy start, your engine will get addicted and it will never start without it.

 

[pvb]

Addicted???

Addicted? Who told you that? Any idea how an inanimate object can get addicted to something? /forums/images/graemlins/confused.gif

 

[VicS]

Re: Addicted???

Thats right engines do not get addicted to Easy Start. What rubbish!

What happens is that people use the Easy Start instead of finding the cause of the problem and fixing it. So it always needs Easy Start. Slowly the cause of the problem gets worse and eventually even the Easy Start doesn't work.

It's the users who get addicted not the engines.

 

[pampas]

Yes engines do become addicted but only in the sense that starting temp is raised thus burning off carbon deposits in areas where a slight deposit is normal. ie rings etc, especially on older engines allowing more blow back to occur leaving less compresion, although with good rings a diesel will start and run without compression. Now some will say that cannot happen, but its true.

 

[Poignard]

Try a teaspoon of oil down the air intake. This gives a temporary increase in compression and improves starting. But it is not a permanent solution and if your engine was in good order you wouldn't need to do it, so sooner or later you are going to have to find the cause of the problem [see suggestions in posts above].

Personally, I wouldn't use Easy Start because it's asolvent and will dissolve any oil coating the cylinder bore.

 

[26ft_bathtub]

Thanks all of you (and any more after this) for your input.

 

[Anonymous]

With any diesel, the most important factor in starting is speed of cranking. That is principally because:-

a) All cylinders leak gas so the compression falls on a slow crank
b) The principle of the diesel is that the compression makes the fuel/air hot enough to explode. If the cranking is too slow it will never happen.

So check cranking speed before anything else - you can usually notice it on an engine you know. Typical problems are low battery volts, bad battery state, corrosion on electrical contacts, very cold engine oil and some unintended load on the crankshaft.

 

[Avocet]

Putting the teaspoon full of oil, into the air intake might not guarantee that it gets into the cylinder - depending on the geometry of the air intake. Probably better to take the injector out and put it down the injecto hole BUT then turn it over by hand a few times before trying the starter because too much oil could cause "hydraulic lock" and damage the engine.

As has been said, engines don't get "adicted" to Easy Start - they just don't fix themselves so the problem that made you reach for the Easy Start in the first place doesn't go away! Easy Start can, however, accelerate engine wear because it can be quite a violent way of starting an engine!

 

[fishermantwo]

I'm with Lemain, start with the basics first. Clean the battery posts and terminals. Check that the battery is fully charged too of course. The engine needs to be spinning fast to fire up properly. The starting easier previously when hot sounds like a failing or poorly charged battery. If the battery is fine then it can only be lack of diesel at the initial start up, the pressure is draining away due to a small airleak in the fuel lines from the injector pump. Air will leak in even though diesel will not leak out.

 

[Freebee]

Re: Addicted???

I think pampas explained how engines get addicted very well, if you use it over a series of starts you will have to use it forevermore as the engine wont start without a liberal squirt of it.

 

[Poignard]

[ QUOTE ]
Putting the teaspoon full of oil, into the air intake might not guarantee that it gets into the cylinder - depending on the geometry of the air intake. Probably better to take the injector out and put it down the injecto hole BUT then turn it over by hand a few times before trying the starter because too much oil could cause "hydraulic lock" and damage the engine.

[/ QUOTE ]

Good points! I am lucky to have the much-maligned [by some on this forum!] BUKH DV10, where removal of the the air filter gives easy access to the inlet valve, and there is a de-compressor and a starting handle.

 

[ccscott49]

I was advocating the use of easy start as a fault finding tool, not as a cure! Does this engine have inlet tract air heaters?
If it does, I would still look at those first, as well as the starter etc. But he didnt mention the starter speed was down.
If you are tied up in a marina, another good fault finding tool, is a hot air gun, pointed down the inlet manifold and then crank the engine, but a simple ammeter inline with the heater plugs will tell you if they are working, or remove one and look. Simple checks first, before talking about compression, which is unlikely to go just like that, plus he would see quite a lot of oil smoke.

 

[Poignard]

[ QUOTE ]
But it is not a permanent solution and if your engine was in good order you wouldn't need to do it, so sooner or later you are going to have to find the cause of the problem

[/ QUOTE ]

What I mean is that the teaspoon of oil will give a better chance of a dodgy engine starting. It is not a cure for other problems but might enable the owner to keep sailing until lay-up time. My own engine doesn't need any "tricks" to get it started, but it did before I overhauled it a few years ago. I am not for one moment suggesting that people should not maintain engines properly.