Emergency Stop Failure

[Chippy]

E Stops are wired so that they "fail safe" ie if the ES fails the circuit is closed

[Gary Prentice]

Its unlikely it was eating its own fumes, if that happens its usually because the crank case is pressurising, does the breather even go to the air intake? That’s an emission’s thing and a lot of small engines (particularly older ones) don’t.

 

The smoke is also not conclusive, all 4 strokes smoke if you put em on their side.

I'll look at the air filter, to check for the presence of oil, just to check it off the list. You're right, of course, about 4-strokes on their sides, but I think this was running for more than a few seconds too. (wonder how the 4-stroke saws have overcome this?)

 

 

 

E Stops are wired so that they "fail safe" ie if the ES fails the circuit is closed

 

I'm probably wrong on definitions, but I thought an open circuit was exactly that- not a complete circuit. Anyway, the ES is working now, as is the ignition, which is the puzzler.

 

We bought this machine used, with issues, a year back. The previous owner had supposedly had a lot of people look at it and couldn't get it to run properly. The main issue was an inline filter full of debris, but to cut a long story short, a short fried a load of wiring. The manufacturers were helpful but didn't have wiring schematics for all the diodes,cutting disc switch & magnetic brakes/clutches and the lombardini schematic didn't exactly match either. I rewired it and got everything working and this happens.

 

So when it rolls over and the ES and ignition both fail to operate, my concern is I didn't wire it correctly:confused1: Hopefully, testing the ignition/ES with the solenoid in various orientations will identify the problem, as Treequip proposes. If not, I'm stuck.

[treequip]

You cant have wired it wrong, the engine requires a live to run when you turn it off on the key it interupts the live and the engine stops, its the same with the ES, it requires a live through that switch to make the engine run, when you press the ES button it latches in the open position and interupts the live and thus the engine stops.

[Breezeblock]

it is possible for a diesel to run on its own oil when it goes belly up as the oil can transfer into the intake via the breather pipework but they aren't an easy thing to stop usually they go bang as rpm is controlled by fuel so free fuel = loads of revs

[treequip]

it is possible for a diesel to run on its own oil when it goes belly up as the oil can transfer into the intake via the breather pipework but they aren't an easy thing to stop usually they go bang as rpm is controlled by fuel so free fuel = loads of revs

 

It needs to be aspirated oil and to get that you generally need to pressurise the sump, a blob of oil in the intake isn’t going to do that for you. If it’s a big enough blob and it gets into the combustion chamber and stop the engine for you.

[Gary Prentice]

You cant have wired it wrong, the engine requires a live to run when you turn it off on the key it interupts the live and the engine stops, its the same with the ES, it requires a live through that switch to make the engine run, when you press the ES button it latches in the open position and interupts the live and thus the engine stops.

 

Understood.

 

What I mean, if I've wired it wrong and the solenoid is still getting a live feed from elsewhere, somehow. Even a short circuit, due to the orientation of the engine on its side. Of course this should be evident by burnt wiring/insulation. As you said, the solenoid coil should either work or not. In this instance it would appear that either it didn't, or the engine received another fuel source. I'm leaning towards the faulty solenoid, which should be easy to confirm. The bonus of the incident is that it may be an early indication of a failing solenoid. Better to sort out in the workshop than stuck out on a site somewhere.

 

[Gary Prentice]

it is possible for a diesel to run on its own oil when it goes belly up as the oil can transfer into the intake via the breather pipework but they aren't an easy thing to stop usually they go bang as rpm is controlled by fuel so free fuel = loads of revs

 

The operator didn't report it as running at a zillion rev's, but then again, he probably wouldn't:sneaky2:

[Justme]

Inside the fuel shut off is a spring that keeps the valve closed unless the current is flowing holding it open. So as long as the spring has enough spring left in it to close the valve even when upside down then the stop button & ignition off will work.

[doobin]

One of our staff managed to roll a stumpgrinder this week. Of concern is his claims that both the emergency stop button and the ignition failed to stop the machine.

 

I only have to read that paragraph and I'm thinking the operator is blaming the emergency stops 'failing' for him rolling it. Rather than him just not concentrating. Do these things have a clutch?

[Tom D]

There's a simple explanation for this, tip an engine on its side and it runs on its own oil, the oil when hot simply burns like fuel. I bet it blew out some blue grey smoke at the time.