Thread: 2.25 Petrol "running on" when ignition off.

My subaru used to do it when it needed a tune up - usually points in this case but can also be timing making the engine hot. The engine becomes a diesel - my subaru would sometimes run backwards for a second or two.

On some carboned up engines the carbon acts as a glowplug and ignites the fuel still in the engine when it turned off and it starts to diesel with more fuel being sucked in.

In the first case a good tune up should fix it - if not maybe a good high rev run to blast off any loose carbon in the combustion chamber etc

Garry

Poor tuning. Get it tuned and get the fuel mixture right (might need to recondition the carbie if the jets are clogged/pitted).

Alan

This engine is rather prone to doing that. Contributory factors - excessive idling speed (specified 500rpm), weak idling mixture, incorrect spark plugs, dirty spark plugs, incorrect ignition timing, low compression, probably a few more factors I can't think of.

Some versions of the Zenith carburetter and others have a fuel shutoff solenoid that cuts the fuel completely when the ignition is turned off to address this problem - but I have not seen one of these on a Landrover.

John

I get that, I find its usually the points gap, my S3 has a Weber on it thats nearly new and I find that the gap is pretty critical, also if I let the engine idle for a few moments, it doesn't seem to run on, I know its not carbon build-up as I have not long had the head off to do the head gasket and had the head skimmed at the same time.

Jack

I had this problem on a Cortina once and it was the low octane petrol I had experimented with; changing to the the highest octane available cured the problem,

Cheers Charlie

Yeah ive found the same.
I accidentally grabbed the 98 hose yesterday and it hasn't done it since!

I still haven't checked the timing, mainly because I don't have a tacho.
The manual says it is extremely important to have the engine running at 800rpm when checking timing, is near enough good enough?

You should be able to buy a multi-meter quite cheaply from any accessory store - the sort that has voltage; dwell; r.p.m., etc. on it. They come with instructions and are extremely useful when tuning older engines.

You won't get the ignition timing exactly right if you don't set the point gap with a dwell meter and the spark plug gap correctly. The engine needs to be thoroughly warm with the choke butterfly completely backed off (worth checking visually) and the vacuum advance tube needs to be disconnected and plugged when using the timing light.

Whilst you are in tuning mode, it would be wise to check the valve clearances and the condition of the high-tension leads; distributor: cap, condenser and rotor arm. I usually buy iridium spark plugs as well, even though they cost more, because they last so much longer and give a better spark.

Stick with the 98 octane petrol as well, the fuel economy is always better,

Cheers Charlie

Thanks for the advice, when this bloody rain stops i WILL be in tuning mode.
(no shed unfortunately..)

I bit the bullet today and bought a Speco in-cab tach, it was cheap and being electronic I assume it will be plenty accurate enough to get a reliable idle speed.
Its all fitted and working great.
I couldn't come at the $150 they wanted for the under-bonnet tuning jobby, it did look nice though!

I need a new rocker cover gasket before I do the valves and all shops are closed...next week!