David_Dickson

Hello,
I bought a new toy the other day.
its a slightly tattier looking one of these...
http://nl.gslopsema.nl/images/news/N...08%20001.1.jpg

Will it start? Will it ****.

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.
Perhaps worn/dirty injectors? if their spray patern wasnt great would this give these symptoms? I would have thought it would smoke a bit in this case.
Any other suggestions?


Also, where would I be likely to find a service manual? google isnt turning up much for me.

Thanks,

Swift Nick

Air leaking back into the fuel system?

Temporarily swap the fuel lines with a bit of clear fuel hose and check for air bubbles.

Alternatively give the fuel pump its own head of fuel and see how it starts.

Nick

PS. The clicky link aint working.

dpb

Its a marine engine ? Try boat yard ? Suprised nothing on yanmar site,
Scooby chick might know

David_Dickson

Its a digger, not a boat, Although Yanmar engines seem to be widely fitted to allsorts.

gallois

a fuel pump problem.....cheapest fix is to fit a decent electric fuel pump in line to provide fuel pressure to start, once started, vacuum is sucking fuel through injectors..

BOB.T

Have you actually had the glow plugs out and checked them? Not just that they are getting power...

Whizz them out, connect some jump leads up to them, positive on the terminal where the wire goes, negative on the body, where the nut shaped bit is. It should glow red hot so you might want to pop it in a vice

I don't mean to teach you to suck eggs but this sounds most likely to me

adehook

as above, pretty common of the yanmar to eat plugs. usually down to the glow timer been faulty and them heating all the time due to them been steam cleaned inside the cabs

David_Dickson

It doesnt have glowplugs. The preheat system is a heating element in the inlet manifold. Diesel from the injector return line is drizzled over this element, igniting in the inlet, which fires up the engine. Its impossible to see it in action, but the element heats as it should and the diesel arrives at the element, so I see no reason why it wont work.