Hi all,
I have a small issue with my 1968 traveller. There are occasions when having turned off the ignition the engine continues to run on, could I ask the possible reasons this might happen? This usually happens when having had her run for roughly 10 min +
Any help connected to this issue would be gratefully received, thank you
Tom
Possible air leak from carb / breather allowing ongoing combustion.I have just had this issue on a rebuilt carb, secondary possibility was a leaky diaphragm on the PCV which not every engine has.
The mixture was also torch and exacerbated by the fact the the choke cable was sticking and not fully returning to the correct idle position.
No doubt others, more expert than me, will have more suggestions, but addressing these cured mine!
caused by hot spots in the engine,which continue to ignite the charge with the ignition off.,Too high idle,too weak mixture.and incorrect timing contribute . Look at the electrodes on the plugs for signs of burning,the tips being eroded is the classic sign. Change for hotter rated pugs ,check mixture ,idle speed and timing. If still no change,try redex upper cylinder cleaner.
Cars in the 80s 90s before fuel injection,which don't have the same problem because the electronic system shuts off the fuel,were fitted with anti run on (,dieseling ),valves which introduced air into the system on switch off,to prevent run on.
The old way was to suggest head off and decoke,but head cleaner is the modern way,unless the car has been run for years too rich and there has been a high build up of carbon.Dribbling water into the carb when running can also clear it out, sometimes,
Some always have this run on ,especially if you have a high comp engine,and the only cure is to fit an anti run on valve, some later mgb had them fitted to the bulkhead so easy conversion to moggies.
Or just put it in gear and stall the engine. Good luck
A lot of people still use the original specified plugs but the fuel has changed (and burns hotter) since then so you really need to change them to 9s instead of 5s (champion numbers).
Thank you all for your replies, after a couple of days of tweaking lots of little things (mixture, static timing, changing plugs) she has stopped running on. I will put this one down to a combination of things together causing this issue. All back to normal!! Once again thanks for every suggestion
Cheers,
Tom
It appears that I may of been a bit quick to think that this issue was gone. Could I get some advise about the different spark plugs some of you are recommending? I will check what plugs I have presently however is it possible that I have too 'hot' plugs? Would this also cause excessive engine heat and possible steam producing?
Sweeny wrote:It appears that I may of been a bit quick to think that this issue was gone. Could I get some advise about the different spark plugs some of you are recommending? I will check what plugs I have presently however is it possible that I have too 'hot' plugs? Would this also cause excessive engine heat and possible steam producing?
Many thanks
Tom
have you got engine overheating ,how do you come to this conclusion,and where is the steam showing ?
Hi all,
Thank you for the advice, for the record the steam comes from the radiator overflow pipe when the engine is stopped (The green pipe that runs down the side of the radiator out the bottom of the engine bay). I will check the spark plugs and post back
Cheers,
Tom
Possibly, apart from the gauge (which I am in the process of wiring in) is there way to tell for optimum coolant flow through the engine?
Many thanks,
Tom
take the rad cap off,start engine and let it tick over until hot, watch the water in the rad and you should see the water start to move through the rad as the thermostat opens, rev the engine,via the carb,and watch the level of the water in the rad,if the thermostat has opened ,the rad is free from blockage and the water pump is working,you should see the level drop slightly ,which indicates that the water is being drawn through the rad and engine.If there is a blockage in the rad or the thermostat is stuck closed,or the pump vanes have rusted away(can happen) then there will be no or very little movement of the water plus watch to see if the water is pushed out of the top of the rad ,this also checks if you have any sign of a head gasket leak,since the escaping gasses enter the water sysem and push the water out .Which would indicate if you have an overheating problem .Its a test worth doing once or twice a year as a preventative measure be careful its hot
If overheating is the cause, run the engine til hot, turn off and feel different areas of radiator to see if evenly heated. A cold area will indicate a blockage.
Kennatt talks sense and Kevin's suggestion is an easy one to do.
There are often reports of scaling on number four sealing up the drain outlet. I have experienced engines wihich have been completely silted at the back of the block with hard water deposits, rust, etc. Knocking out wet liners and seeing the deposits is no longer a surprise for me - but these are rather older engines than A seies austin/morris types. But there were sttill some in the 50/60s that drained engine coolant, in frosty weather, rather than use antifreeze.
