Morris Minor cutting out when warm

Post by **bmcecosse** » Sun Nov 16, 2008 5:17 pm

In a sense - yes! More of an 'insulator' rather than a heat shield though - which would be more like a sheet of metal to keep radiant heat from the exhaust away.

Post by **webbnuts** » Wed Mar 18, 2009 8:44 pm

Thanks for all your suggestions, Father in Law has now dropped the Morris round to my garage so i can get to work. I was actually "lucky" enough to witness the thing break down - after 15 minutes use (regular as clockwork) it cuts out when approaching traffic lights, or a junction.

He called to announce the breakdown, and myself and a neighbour jumped in the car to go and assist. Because it wouldn't start, we could actually work through various things.

The fuel pump was checked first, it was ticking and there was a good squirt of fuel when the fuel pipe was removed from the carb. Next on the list was to check the spark, which is where the problem lied - there was none. We cleaned the rotor arm, the dizzy cap, and plug leads; checked again, still no spark. We checked the coil was live with one of the indicator bulbs, which it was. We removed the condensor from the equation, made no difference. We checked for a spark from the coil by poking a metal pole into the coil's ht lead and holding it against the block. There was no spark, but following subsequent attempts, there was? we reassembled everything and it started, and kept running for another 15 minutes, which was almost long enough to get it into my garage - we had to push the last twenty metres!! It sounds like the coil to me, so i shall replace this first, unless anyone in the know thinks this sounds like something else?

Thanks in advance, and for taking the time to read this,

Sam.

Post by **PSL184** » Wed Mar 18, 2009 9:26 pm

As the coil has been replaced twice (at least) already I would doubt it - Unless you have been very unlucky or unless you are fitting the wrong coils? I would check for old, corroded or dodgy wiring to the coil first....

Post by **bmcecosse** » Wed Mar 18, 2009 11:30 pm

You certainly did a good and thorough trouble shoot there! I would say it's the condenser heating up and causing the problem. You say it was 'removed from the equation' - did you fit another in it's place ? Surely unlikely to be the coil - unless wrong coil supplied. Minis use a 9 volt coil - and this if used on 14 volt Minor will indeed overheat greatly ! Does the coil feel HOT to the touch? You can expect it to get warm, but should not be hot.

Post by **Kevin** » Thu Mar 19, 2009 12:48 am

Now that's what I was wondering Roy if a Ballast Coil had been fitted by mistake.
I always though Mini's used the same coil as the Moggie until the early eighties.

Post by **bmcecosse** » Thu Mar 19, 2009 2:27 pm

Yes - until the early eighties. But any Mini coil being sold now is likely to be for the ballasted ignition - and they may just assume it will also be suitable for a Minor!

Post by **webbnuts** » Fri Mar 20, 2009 7:40 pm

Right, well I bought a new condensor and coil, and got home all excited - fitted them but to no avail. More trouble shooting! I put a spark plug on the king lead from the coil and cranked it over, initially there was no spark, then a really really weak spark the second time. I replaced both connectors to the coil, as they were quite grubby, but this made no difference. Where do the wires for the coil originate from, could i replace them from source to coil to rule out a short or bad earth perhaps?

flat battery now so its on charge ready for more fun and frolics tomorrow. Cant help thinking i didn't need to buy that coil!

Thanks,

Sam.

Post by **PSL184** » Fri Mar 20, 2009 8:08 pm

PSL184 wrote:As the coil has been replaced twice (at least) already I would doubt it - Unless you have been very unlucky or unless you are fitting the wrong coils? I would check for old, corroded or dodgy wiring to the coil first....

Hmmmmm !!

Check the fuse box....

Post by **webbnuts** » Fri Mar 20, 2009 8:14 pm

I checked the ignition fuse (the big fat one) and that seemed ok. There was a spark the second time just really weak. Tother looked ok but i have misplaced my multimeter.

Post by **bmcecosse** » Fri Mar 20, 2009 10:53 pm

Coil has main feed from the Ign switch to +ve connection on a -ve earth car, and the other wire goes from coil to dizzy. The little 'low voltage' wire inside the dizzy can become very frayed over time - and either not make good contact, or cause a short. But doesn't explain the 15 minute 'time out'!

Post by **PSL184** » Sat Mar 21, 2009 12:27 am

webbnuts wrote:I checked the ignition fuse (the big fat one) and that seemed ok. There was a spark the second time just really weak. Tother looked ok but i have misplaced my multimeter.

As standard there is not "a big fat one". Both fuses should be rated at 35 amps....

Post by **crossword** » Sat Mar 21, 2009 9:54 am

This sounds very much like my current problem. It has been steadily worsening over the last few months . Now i have started to tackle it I have replaced the air filter, rebuilt the carburetter , replaced points & condenser , cleaned the filter in the fuel pump , added an inline filter between pump & carb . The latter to easily check for the presence of fuel & to remove the suspected muck coming from the 50 year old tank , there is fuel but not muck . The tank was drained last year when i needed to fit a new fuel pipe , the fuel was clean . Today i plan to strip & rebuild the pump with a new diaphragm . Yes it ticks properly . When it cuts out there is fuel in the float chamber at approx 20 mm below the top , does anyone know if that is OK ?

I am not hopeful of fixing it today as my spare fuel pump does not fix it but is of questionable history .

My spare coil does not fix it .

I feel that i may have something too large to drain from the smallish hole in the bottom of the fuel tank which is blocking the pick up pipe .
Last Sunday I had to be towed home .
I wish you good luck with 'our' problem , just believe it can be fixed

Regards Andy

Post by **bmcecosse** » Sat Mar 21, 2009 9:58 am

When it 'cuts out' - if there fuel in the carb - it's not a fuel problem!

Post by **crossword** » Sat Mar 21, 2009 10:20 am

I thought it could be if the level was too high , as the various manuals I have suggest that the level in the jet tube is only 1/8" below the top normally, if the float allowed the level to be 1/4" too high , I think starting would be OK but running warm would be difficult as though the choke was pulled out . This is how it feels before cutting out completely . I have fitted a new inlet valve as part of the carb rebuild . My carb appears to be the later HS2 with a spring loaded inlet valve , I believe that float level on it is not adjustable . I do thank you for the observation about fuel in the carb though . Difficult to explain but the way it dies " feels " fuel related . Maybe I am now wearing blinkers .

Regards Andy

Post by **bmcecosse** » Sat Mar 21, 2009 5:38 pm

Well - it could be 'too much' fuel problem (due to leaking float valve) but your efforts seem to be devoted to searching out 'lack of fuel' problem ? If indeed the carb is flooding - then it will sound very rich (spluttering etc) just before it dies - and the plugs are likely to be wet with fuel.

Post by **Kevin** » Sun Mar 22, 2009 8:43 am

Hi Sam just a thought as you haven't mentioned it I assume you have checked the points are OK and that the low tension lead in the dizzy is sound, you said you cleaned the plug leads but nothing about testing them, also the cap have you looked at it really closely to make sure there is not a partial hairline crack in it and that the plunger in the top of it is moving Ok. You have mentioned your coil test but what sort of spark do you get if you put one of the plug leads with a plug in it against the block, and also what is the spark like at the points.
Sorry if you have tried all of these its just that you didnt mention them.

Post by **webbnuts** » Mon Mar 23, 2009 9:39 pm

Hi, Thanks for all the help and support!

The cap looks fine, (recently replaced as was the rotar arm). I'll check the wire in the distributor isn't earthing out inside.

I thought it could be a bad earth, so added a makeshift earth lead which didn't help, then tried putting a wire from the positive battery terminal to the positive coil terminal. The morris sprang into life and ran on tickover for twenty minutes without missing a single beat (with the wire removed). We got in and went round the block. The Morris pulled cleanly in all gears, and ran smoothly along the straight. approaching a roundabout, i dropped down to second, braked and the ignition light came on and it died, we were still free wheeling so bumped it in second and after coughing a bit it picked up and we continued on our journey, it seemed that every time we slowed down it died, and eventually, when i pulled into my drive, it spluttered and blipping the throttle didn't revive it. It wouldn't start again afterwards. Ten minutes later it started, but only by flicking the starter quickly, holding the starter on continuously wouldn't start it. Sorry for the essay but I just want to give as much info as possible in the hope someone can shed some light on it!

Thanks for all your help,

Sam.

Post by **bmcecosse** » Mon Mar 23, 2009 10:19 pm

Is the piston in the carb free to rise and fall ok ?

Post by **mrbenn** » Mon Mar 23, 2009 11:06 pm

I have a problem with cutting out when the engine was warm and coming to a halt a couple of years ago. Changed the LT wire on the side of the distributor and it hasn't done it since *touch wood*.

Post by **nigelr2000** » Tue Mar 24, 2009 8:31 am

I had the same effect 2 weeks ago but more obvious as it was at night and the lights died as well. It turned out to be the connector to the regulator ( A or A1 don't remember which) ) was corroded. The circuit is from the battery to the regulator then from the other spade on the regulator to all the other electrics so when the fault appeared the car was running off the dynamo with no 12 volt feed from the battery hence why it died when slowing the engine speed. I found it by turning all the lights, heater and wipers on and checking using a voltmeter for voltage drop. NB also found the dodgy connector with my finger as it was so hot it burnt me (ouch) still got the scar !

Take a look at the sticky in electrics to see the circuit, mine was weird for a while with the indicators stopping flashing and the lights going dim on tickover which i thought was normal but now no longer happens.