small diesel engine not starting.

[dave21478]

Hello,
I bought a new toy the other day.
its a slightly tattier looking one of these...


Will it start? Will it f***.

Its a 3 cylinder Yanmar diesel engine with a wee turbo on it.
The pre-heat works fine, but the engine turns over and over without a hint of firing. But, give it a tiny (less than half a second) puff of coldstart spray in the intake and it fires up first turn and once running, works perfectly. Power is good and it doesnt smoke at all.
Kill the engine and if you restart within a couple of minutes, it will start ok, but any longer and it will need another puff of coldstart to get it going.

preheat definately works.
I havent yet done a compression test, but given how well it does run, I don't suspect anything wrong there.
Perhas worn/dirty injectors? if their spray patern wasnt great would this give these symptoms? I would have thought it would smoke a bit in th case.
Any other suggestions?

Thanks,

[tonka12]

how do you know the preheat works ? if youve got power at the heater plugs it doesnt meen the plugs are glowing . i would take them out and test them with some jumpleads and a battery just a thought

[Deleted]

when you pop the plugs out fire them up and see if they heat right at the tip and within 5 seconds on a good battery,
my first thought was stop solenoid but as it runs once its had a sniff of ether then its probably working ok, also check for air leaks as the pump turning at crank speed might not draw enough fuel/air but when running its going a hell of a lot quicker and might run fast enough to self bleed as its running

[dave21478]

its not traditional heater plugs as per diesel cars - its a cyptic thing in the inlet manifold after the turbo - a heater element gets chuffing hot (burnt fingers to proove) and diesel from the return pipe from the injectors drips onto it and burns in the inlet, firing the engine up from cold.
It sounds heath-robinson, but I have a wee yanmar compact tractor with the same system which works fine.

[euro12]

Jun 1, 2009 17:41:06 GMT dave21478 said:

Hello,
I bought a new toy the other day.
its a slightly tattier looking one of these...


Will it start? Will it f***.

Its a 3 cylinder Yanmar diesel engine with a wee turbo on it.
The pre-heat works fine, but the engine turns over and over without a hint of firing. But, give it a tiny (less than half a second) puff of coldstart spray in the intake and it fires up first turn and once running, works perfectly. Power is good and it doesnt smoke at all.
Kill the engine and if you restart within a couple of minutes, it will start ok, but any longer and it will need another puff of coldstart to get it going.

preheat definately works.
I havent yet done a compression test, but given how well it does run, I don't suspect anything wrong there.
Perhas worn/dirty injectors? if their spray patern wasnt great would this give these symptoms? I would have thought it would smoke a bit in th case.
Any other suggestions?

Thanks,

[euro12]

Hi
I have the same excavator
Can you give me the hydraulic pump number and type
Because mine right now has a different pump not the original and is not working right
I'm trying to get the original pump info but no luck so far
Thank you