OT: Why can't a petrol engine start itself?

On MOST diesels the shut-off kills the fuel which is why if you hole a piston or a turbo seal the damned things will take off ontheir own. MOST diesels have NO air control

On today's engines the key shuts off the ignition AND the fuel. Virtually immediately.

The 2 strokes shut off fuel and air because they were likely to take off and run on crankcase oil if a blower seal got loose.

Haven't seen an air shutoff on a 4 stroke - could have used one a few times!!! Had a big Allis loader put a pair of coveralls right through the engine before slamming a 2X6 over the air intake.

Idling too fast and or a vacuum leak or running too hot (late timing) on a rocket and you can almosrt DRIVE it with the spark shut off - particularly on regular gas. Didn't need much carbon

Had a 1275 Stage 3 cooper engine in a Moke at the school in Zambia that WOULD drive into the shop with the spark shut off - if you feathered the clutch and didn't stall it. Over 15:1 CR and 81 octane gas - - - On 100 octane AvGas or race fuel it was apparently SCARY!! Couldn't buy good enough gas inthe country to run it after independence

I had a petrol engined Renault Espace that would do that. The carburetttor was f***ed and it often flooded itself, hence there was loads of spare fuel hanging around. Easy enough to stop. Place in gear, then let out the clutch with the brakes on.

He talks in correct English. No accent whatsoever. No stretching vowels like the yanks do.

Dean Hoffman posted for all of us...

In the early days of emission engines when the systems were mechanical ther e would be a condition called 'run on' when the ignition was shut off. It sounded like a mechanical coughing fit. Some cars had to be in gear to stop it. Clare can explain better than me.

On Fri, 23 Mar 2018 20:17:04 -0000, Tekkie=AE wrote= :

te:

I had that with my 1988 Range Rover which had been badly converted to us= e petrol or LPG by the previous owner. It was also impossible to start = it on petrol, even though that was what you were meant to do. It only s= tarted on LPG, after several tries, often with an explosion in the exhau= st, which scared the s*it out of anyone stood behind it.

-- =

If debugging is the process of removing software bugs, then programming = must be the process of putting them in.

The majority of the ones I've had turn off the electrical power to the ignition coil as well the electric fuel pump. I've had a couple of much older ones that didn't use an electric fuel pump. In those cases, I believe it was just cutting power to the coil.

Ahh. Learn something new everyday. :) Thanks.

Virtually every car since the early nineties has been fuel injected - which basically requires an electric fuel pump - and electricity to open the injectors. The key shuts off both along with the ignition.

Well unless you have a perfectly sealed system....

rbowman posted for all of us...

offices and industry. I was working with a lot of aluminum so I was using hardware and metalworking techniques that wouldn't be out of place in the aircraft industry. Then there is the technology transfer from the military to the civilian world once it becomes declassified. My older brother was a Green Beret in Vietnam and he told me of a tiny radio they were using but couldn't tell me much more because he was still constrained by his security clearance. I imagine the military was using spread spectrum technology while he was serving there in the 1960's long before we civilians ever heard of it. ^_^

Looking at the connector I see a clamp. How does the hose fit into the connector and seal? It does not look like a barbed fitting would work and just the clamp / hose connection wouldn't be airtight. Are they threaded & the hose has a press fitting on it?

James Wilkinson Sword posted for all of us...

I saw someone who connected the cables the way you described and proceeded to blow the top of the battery off and have his face and eyes splashed with acid.

The purpose of the chassis connection is to keep the arc away from the battery for this issue.

Clare Snyder posted for all of us...

Not to be dense, but how do they air up if they use an air starter?

rbowman posted for all of us...

Except if it's the opposing political party.

(I'm sorry but I could not resist)

On Fri, 30 Mar 2018 19:31:02 +0100, Tekkie=AE wrote= :

oblem, plenty fresh air for any hydrogen from the battery.

ead to the chassis, not the battery. Why? You can get a spark off the = positive anyway....

the +ve of the two batteries together, then started the dead car. And I= don't run the other engine first either, you just don't need it. If th= e good battery can start it's own car, it can start the other car.

There is no gas present when you connect the lead. Gas is created when = charging (or more specifically OVERcharging) a battery.

-- =

Little Tommy took a drink but he will drink no more. What he thought was H2O was H2SO4.

On Fri, 30 Mar 2018 19:31:02 +0100, Tekkie=AE wrote= :

oblem, plenty fresh air for any hydrogen from the battery.

ead to the chassis, not the battery. Why? You can get a spark off the = positive anyway....

the +ve of the two batteries together, then started the dead car. And I= don't run the other engine first either, you just don't need it. If th= e good battery can start it's own car, it can start the other car.

Funny how I've never seen anyone do that. Everyone just connects the ba= tteries, never seen a problem. If batteries were in the habit of giving= off explosive gases, there would be big problems with cars randomly cat= ching fire.

-- =

John Montagu: "Sir, I do not know whether you will die on the gallows or= of the pox." Samuel Foote: "That will depend my lord, on whether I embrace your lords= hip's principles or your mistress."

On Fri, 30 Mar 2018 19:32:52 +0100, Tekkie=AE wrote= :

Isn't he talking about donating air to another guy's rig?

-- =

The fact that a believer is happier than a skeptic is no more to the poi= nt than the fact that a drunken man is happier than a sober one -- Georg= e Bernard Shaw