Engine run on

[AlanSills]

HI HAS ANYONE HAD A PROBLEM WITH ENGINE RUN ON WHEN TURNING OF ENGINE

DETAILS: 1967 1098 STD ENGINE

IGN TIME SET AT 9/1600 WITH OUT ADV
CO SET 3.5 - 3.75
CHAMPION N5C PLUGS
POINTS SET AT 15THOU

HEAD DECOKED 2K AGO

CAN ANY ONE HELP
THANKS IN ADVANCE

ALAN

[PSL184]

There is no "book" value for timing - each engine will need fine adjustments to get it correct. Try backing off the timing to around 5 deg and see if it still does it.

[mike.perry]

I occasionally get the engine running on a couple of beats on my 1275 traveller but I haven't done anything about it yet.
As far as I am aware it is caused by soot deposits in the combustion chambers or exhaust ports glowing hot and igniting any fuel residue.
Check the condition of the plugs for starters.

[StaffsMoggie]

1098 Moggies dont usually suffer much from running on. Its usually the mixture too weak or the ignition timing too far advanced. When timing Minors I have found that no two are the same and usually set them up by trial and error until they behave. Have a look at the colour of the plugs, they should be a nice medium brown, if they are whitish then richen it up a bit.

[bmcecosse]

Welcome to the forum Alan! The spark plugs you list are not ideal - better with extended nose plugs - Champion N9Y are good for a 1098. The ignition timing should be advanced in stages until the engine 'pinks' slightly - and then retarded slightly until the pinking disappears. Try changing to a different petrol - and even just a good hard run on the Motorway may clear away any deposits which are glowing and causing the run-on. Is the idle speed set as low as practical - and is the engine running very hot ?

[AlanSills]

HI, THANK YOU FOR THE WELCOME. SORRY AS CAN NOT SEE FIRST NAME UNABLE TO USE.

ENGINE WILL NOT RUN BELOW 750 RPM
HAVE TRIED TO RETARED TIMING BUT WILL NOT CHANGE OTHER THEN LACK OF POWER WILL
HAVE RAN RN9YC AND RN9YCC BUT STILL PROBLEM
CHAMPION TECH ADVISED ON N5C AS LOWER TEMP
I WILL THIS WEEKEND TRY NGK AND RE-TRY RN9YC
ENGINE RUN AT NORM TEMP
AND ADVISE

THANKS FOR INFO

REGARDS
ALAN

[bmcecosse]

Something seriously wrong if the engine won't run below 750 rpm - how do you know anyway?? Don't waste money on more plugs - you've tried enough to know it's not that! You need to get the idle speed down - slacken the choke and throttle cables - one may be too tight - then back off the 'fast-idle' screw on the choke mech -and then lower the speed (if still high) on the normal idle screw. It should be able to idle at ~ 400 rpm - although 500 may be better in winter. Then - take it for a good hard run to clear out the rubbish! If still running on - there is a trick used by some Mini lads to clear the engine without removing the head - by simply running the hot engine at a fast idle - and dribbling water into the manifold - by sucking it up through the little tube that conects manifold to dizzy. A cup-full is all it takes - so they say - followed by a good blast down the road to blow out the gunge and dry everything off. Worth a try - doesn't cost anything!
Edit - If you don't have a manual for the car - pm me and I will give you the link to a free download of the Leyland manual.

[Mogwai]

If you dont find any obvious mechanical or fueling faults may be worth trying a higher octane fuel for a bit to see if it helps

[AlanSills]

HI
THANKS FOR REPLY I HAVE TRIED HIGHER OCTANE FROM BOTH BP AND SHELL AS SHELL IS HIGHER STILL WITH SAME PROBLEM

REGARDS
ALAN

[DAVIDMCCULLOUGH]

My blue minor runs on, the only cure I found was to use petrol additive with octane booster. I use the miller one. None of the other Minors have ever suffered this problem though and I use the same petrol and plugs!

[bmcecosse]

At the end of the day - Running On is caused by something glowing red inside the combustion chambers - enough to ignite the incoming charge and so keeps the engine going. So if all else fails - it's off with it's head and a thorough decoke - and removal of any sharp edges and general rough bits with a grind stone or even just with a file for the edges.

[dalebrignall]

mine suffers from this a bit,and the engine has only done 8000 miles im going to try some redex down it and go to higher octaine petrol