How does engine stop

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vic008

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My little 2 cyl diesel has no provision for stopping it.ie no stop fuel cut off magnet. what would be the best way of setting something up? A fuel cut-off cock? Adjust throttle lever to do it by reducing revs ? With the usual setup where you are basically stopping the fuel supply, why do you not get an airlock and need to bleed every time?
 
What make of engine is it? Must have a way of stopping it. Usually way is fuel shut off with acable or rod to operate the lever, but may be an electrically driven solenoid activated by a switch. Old engines sometimes used a decompression lever on the exhaust valve.
 
neilf39 said:
If its a diesel then it must have a decompression lever. Some have a solenoid operated one but there is usually a manual one too. with no compression the engine won't fire.
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Yes - and on some older diesels, this is the normal means of stopping it. In the 60s, we had a Sabb disel, and the usual way of stopping that was with the decompresser lever at the top of the cylinder head.
 
AntarcticPilot said:
Yes - and on some older diesels, this is the normal means of stopping it. In the 60s, we had a Sabb disel, and the usual way of stopping that was with the decompresser lever at the top of the cylinder head.
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...whereas on middle-aged ones like the Yanmar in KS, the manual warns you against stopping it with the decompressor.

Pete
 
The only ways to stop a diesel engine are toremove the fuel or air supplies or remove compression.
Some older engine are meant to be stopped by closing the throttle but have a spring loaded safety system to avoid inadvertently stopping whilst in neutral this was a problem when single lever controls became a standard requirement so an addition pull to stop cable was added.
Stopping by decompressing as I recall decreased the life of exhaust valve!
A solenoid is only an electrical actuator.
 
LittleSister said:
How?

No use to the original poster, but my old AJS 500 single (petrol engine, magneto ignition) was, like many motorbikes of its day, stopped by lifting a valve (via a cable and a lever on the handlebar) to decompress.
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I'm sorry but the decompressor on those bikes was used to aid starting.To stop the engine the magneto was earthed.
 
LittleSister said:
Not on my bike (and also some mates' bikes).
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Not wishing to argue ,magnetos had cut outs since before the war.My own 54 Norton Dominator and a friend's 350cc matchless of similar vintage had cut out buttons connected to the magnetos.It was possible to stop a bike engine by decompressing it but it was mechanically unsympathetic as the mechanism wasn't meant to cope with the stresses involved.I would venture that your bike and perhaps your mate's were missing the cut out wire and made do with the decompressor.Not all machines like twin cylinder ones or those with smaller engines had need for a decompressor and still had a way of shutting the engine off.
 
Mine - a Farymann cement mixer engine - also warns against decompressing to stop it. It doesn't say why. It has a cable operated stop pull thingy, which effectively closes the throttle down to zero - i.e. beyond the normal stopping point for the throttle control.
 
You CAN stop an engine with a decompressor,but the maker will have provided a better way,which does not send fire and brimstone up past the exhaust valve.
Either there is a little fuel cut off lever on your injector pump,or the fuel lever has a bit of travel the other way from tickover.
Blocking the air intake will always stop any engine! cheers Jerry
 
scottie said:
Agreed

However" throttling " is easier to say than "than adjusting the governor control arm" and is understood as such
We're some older ford engines not controlled by adjusting the air inlet?
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Yes Ford 4D,6D as in Fordson Major tractors,Parsons Pike marine units etc,had a throttle in the air inlet which was controlled by the driver's foot. Thence vacuum tubes,one from upstream,and one from downstream of the throttle butterfly led to a diaphragm connected to the fuel rack on the Sims injector pump,and the difference between atmospheric pressure and the inlet manifold depression moved the rack.
I have driven the tractor version, and I had one in a boat, and it works fine! But I would like to know just why they did it that way??
 
LittleSister said:
No compression, no fire and brimstone, surely?
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Good point..only with petrol engines such as motorbikes.
Thinking about it,decompressing would still not be a good way to stop any engine,it would waste fuel and leave a few injector-squirts of fresh fuel in the cylinder and exhaust manifold or pipe. But hey whatever
 
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jerrytug said:
Good point..only with petrol engines such as motorbikes.
Thinking about it,decompressing would still not be a good way to stop any engine,it would waste fuel and leave a few injector-squirts of fresh fuel in the cylinder and exhaust manifold or pipe. But hey whatever
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However, some older engines were designed to be stopped that way - the Sabb single cylinder diesel (fitted on the Halcyon 27 in the 1960s, but old technology even then!) certainly was; there was no provision for stopping the engine other than using the decompresser.
 
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