2.25 wont shut down

[354 chamberlain]

During the preservation project of my 71 lwb I fitted an electronic distributer and a weber carby the problem that I have is that I have to stall the engine to stop it running on every time I switch it off when it is hot . I have played with the timing and moved it radicaly in either direction with no change also tried 95 fuel with out any change . I don't know what it was like with the zenith and points distributer . any suggestions ?
Doug

[bee utey]

Sounds like your cylinders are carboned up. Too rich mixture maybe? Most modern carburetors have idle stop solenoids to prevent running on.

[Busted Syncro]

G'day Doug,

The run on after the ignition switch is turned off maybe caused by the following:

This could be happening because you have a very good tuneup and electronic ignition and engine is hot.

The alternator indicator light diodes are feeding back 12 volts to the electronic ignition circuit via the indicator lamp when the ignition switch is turned off and while the engine is running down. (The symptom is when the ignition is off the indicator lamp is "on" as the engine runs down.)
The fix is fitting a diode in the lead that goes from the indicator lamp to the "ind" terminal on the alternator. The polarity of the diode is Anode to the lamp and Cathode to the "ind" terminal. (The cathode end of the diode has the white band on it.)

The indicator lamp will work normally however, the diode will block the voltage from the "ind" diodes to the lamp with the ignition switch off.

Best way is find the leads that go to the lamp then identify the lead that goes to the fuse box. The diode goes in the other lead. I use 3amp diodes because they have thicker leads and use heat shrink to cover the wire and diode. (I also make up a circuit board sometimes with 6.3mm male lugs at each end and use female 6.3mm terminals on the wires, then heat shrink)

Hope this makes sense and fixes your problem.

Chris

[JDNSW]

First thing - check whether the running on is due to continued spark, or whether it is self ignition. A neon light on a spark plug lead while it is running on would immediately answer that. If there is continuing spark, one suggestion for this is given.

If it is self ignition, and this engine is a bit prone to that, the most likely reason is excessive idling speed - should be no more than 600rpm, and preferably around 500. Other reasons will be, as mentioned, carbon deposits in the combustion chamber or plugs are too hot or have worn electrodes.

Hope this helps.

[354 chamberlain]

Thank you for your replies, I can discount the alternator as I have just fitted a new 65 amp unit an I was playing with the timing with the alternator removed .I think the spark plugs may be a part of the problem as it is fitted with N12YC which are for the high compression engine ,the vehicle is an ex telecom unit and might have the low compression engine which uses a cooler N5C plug . I will drop the idle and lean off the mixture screw and see what happens ,if no change I will fit the cooler plugs .
Doug

[Dgd69]

Thank you for your replies, I can discount the alternator as I have just fitted a new 65 amp unit an I was playing with the timing with the alternator removed .I think the spark plugs may be a part of the problem as it is fitted with N12YC which are for the high compression engine ,the vehicle is an ex telecom unit and might have the low compression engine which uses a cooler N5C plug . I will drop the idle and lean off the mixture screw and see what happens ,if no change I will fit the cooler plugs .
Doug

Hey Doug

I have a ex telecom Land Rover Ute have not seen to many around is yours the telecom orange as well any pics

[JDNSW]

High compression heads can be easily (but not totally reliably) identified -

The high compression head, and all later production heads, have raised, roughly square boss cast on top of the head, outside the rocker cover, next to the carburettor. If it is a high compression head ex-factory, this will be stamped with an "8", if low compression, it will have a "7", or be unmarked.

The only catch is if it was marked and the mark is illegible, or the compression has been increased by skimming the head post-manufacture, but no change to the mark.

Early low compression heads do not have the raised boss.

The vast majority of 2.25s sold in Australia were low compression, and high compression ones may have been only a few of those imported fully assembled and perhaps late S3.

[354 chamberlain]

Dgd69
having trouble replying directly to your post .
Mine has been resprayed battleship grey but the chassis was still orange as well as overspray under the guards and floor . I have since resprayed it black after some rust repairs . It has no hand throttle fitted and the passenger seat well is set up for second battery .

[Markf]

For what it's worth my SIIA (when I had it) ran on and on and on and on during summer when it was hot. I had a couple of other issues which required removal of the head and the amount of carbon build up in there was EXTREME. After I put it all back together the running on stopped.

[354 chamberlain]

After chasing around various web sites I lowered the idle as low as itwould go the adjusted the mixture screw until it was runnung smooth then readjusted the idle up a bit but still very low ,reset the timing (I did that first) and allow the engine to idle down and cool for about 30 seconds before turning off , works most times and if it does run on it is very short . Will see if cooler plugs help when they arrive .
Doug