Why does a diesel engine start poorly

[SvenH]

It seems that some diesels start easily and some take tens of seconds.

I count myself luck with my yanmar 2gm which starts within 10 (usually within 5 seconds or something) but my neighbours volvo can take up to a minute.

Can that be because of age/heavy usage, like reduced compression? Poor preheating? (My yanmar does not preheat, maybe the volvo does?

 

[colind3782]

All of the above but it could also be down to a knackered battery not turning it over fast enough.

 

[savageseadog]

Injector spray pattern, low compression, poor quality fuel, low temperatures

 

[Momac]

My engines usually start easily with no throttle applied.
The only exception being after being unused for an extended period.
They are Volvo. However I don't think the brand of engine is significant.

 

[Tranona]

Depends on the type of Volvo. Old ones were slow starters, but 20x0 onwards have glow plugs and should start instantly. This is the case with both 2030 and D1 30 that I have owned. If they don't then all of the things mentioned so far could be the problem.

 

[SvenH]

Old ones were slow starters

Ah, my neighbours volvo is 30 years old...

 

[MoodySabre]

Ah, my neighbours volvo is 30 years old...

Then he needs to follow the starting procedure for these old engines that have no glow plugs.
Half throttle (or more), pull the stop cable right out and push it back in, turn the key.

 

[JumbleDuck]

Starting of my 1GM10 was transformed when I replaced the head and precombustion chamber.

 

[penberth3]

Starting of my 1GM10 was transformed when I replaced the head and precombustion chamber.

That reminds me, isn't there a difference in starting performance with direct and indirect combustion? Can't remember which one starts easier.

 

[Neeves]

Blocked exhaust manifold, again.

 

[Saltsail]

Check anodes! Check pipes, piston rings is less common problem, fuel primer valve, try pumping it up, before starting maybe not enough fuel! My engine stood for 20 years, it's started like a baby!

 

[SvenH]

Then he needs to follow the starting procedure for these old engines that have no glow plugs.
Half throttle (or more), pull the stop cable right out and push it back in, turn the key.

Ah, I'll pass on the tip, thanks.

 

[pvb]

Then he needs to follow the starting procedure for these old engines that have no glow plugs.
Half throttle (or more), pull the stop cable right out and push it back in, turn the key.

That's the most likely explanation. The cold start procedure works well.

 

[penberth3]

...pull the stop cable right out and push it back in...

Another thing there, if it is a cable and not a solenoid. Make sure the cable is free and properly adjusted and the lever is actually returning to the "run" position.