Morris Minor Owners Club

hi,

my morris stopped working over christmas. the symptoms; lack of power under load, coughing, spluttering and backfiring followed by engine cutting out then not being able to start engine for about 5 mins.

RAC men's dignosis - rotor arm, condenser, dirt in fuel blocking carb, too much fuel going into engine.

work done so far - changed rotor arm, changed plugs, changed condenser, changed distributer cap, checked points clearance, cleaned carburettor, installed in-line fuel filter, checked float bowl lid and float, fuel pump seems to run fine.

The engine will start and is ok when just idling but when the throttle is opened the engine starts backfiring, the sparks at plugs 2+3 seem to lessen (?), then the engine stops and won't restart for about 5 mins. when trying to restart immediately after stopping the plugs don't spark.

hope this has enough detail for people!!

any ideas where to try next for the problem please, any ideas would be useful.

Thanks in advance for your advice and help,

Pete

when trying to restart immediately after stopping the plugs don't spark.

Ok, how have you confirmed there is no spark at all the plugs and how have you confirmed 2 & 3 spark less when running.
Have you checked that the low tension lead is Ok and what about the HT leads, and does the coil get very hot when its been running.

I bought a set of spark viewers from halfords although I don't know if they show strength of spark or just a yes/no. (hence the (?)). The leads are fine. The coil was changed in the summer but has not been checked.

Pete

Ok, it sounds like its ignition related then if you are losing the sparks, did you replace the items one at a time to see which if any were faulty or did you just change the whole lot at once.
There have been some bad batches of rotor arms around that have been causing problems also it the spring contact in the new cap working alright, but 1st thing when it stops running do you still have a spark at the points, also check the low tension lead and coil connections to make sure nothing has an iffy connection.

Bey a new 12V coil and see if swopping it with the original WHEN THE FAULT
OCCURS NEXT TIME to see if the engine will then start. If it cures the fault then fine, if it doesn't then you have not wasted your money as you should
always carry a spare coil in the car.

Hi I don't think the problem is with the coil as you still have a spark at 1 + 4 so the fault must be either dizzy cap tracking across terminals or spark plug braking down under compression. You could try changing the plugs from 2 + 3 to 1 + 4 And vice versa and see if the fault changes from 2 + 3 to 1 + 4. If so it's the plugs. Also sometimes by checking for the fault in the dark you can see dizzy cap or plug lead tracking to earth. I hope this is of some help and you get it sorted Pat.

Sounds like coil to me - provided you are SURE the fuel pump is working ok - it may be sticking and the engine just using up the fuel in the carb bowl each time. Try taking the fuel pipe off the carb and putting it into a petrol can (NO SMOKING!) and then see if it can deliver a steady stream constantly. The RAC was obviously a 'big help' - his idea was both shortage of fuel - and too much fuel !! Surprised he didn't sell you a battery - that's what they are famous for!

If it reliably stops every 5 mins then I agree wholeheartedly with bmcecosse, coil is the most likely explanation if you have eliminated fuel flow, given that you already changed the condenser.

I agree, there's been plenty of posts over the years like this and it's usually the coil - often because the wrong type has been fitted. Did you get yours from a reputable Minor specialist?

Sounds like the RAC man just read the table of possible causes from the Haynes manual!

ok, a new coil has at least meant that I could get back to bath from andover (C50miles) with the engine only stopping twice and me being able to restart as soon as it stopped. We will leave that fault for later however as a new fault has occured which I will describe now,

The car will start fine, sounds good etc. after going between 2 and 20 metres the engine will stop. It will take a lot of effort for the engine to restart and when it does it will be very rough and periodic in fast and slow turn over. If the throttle is touched at this time the engine will stop. after a period of time of about 5 minutes the engine will suddenly start running fine and will pose no further problem for the rest of the journey. it will also stop and start without problem for a good while after. When trying to restart the engine after the intial stopping it will sound as if the engine is working against a load and pressure will be building up in the radiator which will expel water from the overflow or the top if i take the cap off.

everything above still stands as to what has been changed etc.

any help much appreciated,

Pete

Ok, assuming that the new coil is fine, it does sound like an intermittant electrical problem. I recall a similar post where a very thin wire on the distributer had frayed or broken and the car kept cutting out.

Check the connections to the dynamo as well. If one is these is loose it can stop the engine.

the radiator which will expel water from the overflow or the top if i take the cap off

That's normal.

Don't fill it right to the top in the first place! A full ignition overhaul is what's needed - plus thorough check of the wiring - especially loose connections at the coil and dizzy. You could by-pass all the wiring for a trial - run a wire to the coil from any power point, and another from coil to dizzy. Does it run perfectly now ?

Are you absolutely sure you've checked the fuel flow. If you have a non standard lockable fuel cap it can cause airlocks, your symptons would be a pretty severe case though, so I think I fall on the side of electical connections and wiring if coil and condenser and rotor arm are known to be good.

The little - 'low voltage wire' in the dizzy gets tired after a while - new one is again only pennies.