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Post by jeff on Dec 20, 2020 12:49:08 GMT
Hello again folks.
First, I'm happy to say that my MK1 Morris just passed its voluntary MOT with a clean bill of health so thanks to all those who gave advice on rebuilding suspension etc etc.
Now, I have a wee problem when starting hot. From stone cold, she fires up after 4 or 5 turns no problem and continues to run very well.
However when hot after a good run
If Its switched off for a few minutes, it really struggles to start. It fires straight away but stumbles causing the starter to disengage and spin. This can happen several times before eventually starting and then run without any problems until stopped again.
I dont think its the starter or ring gear as without fuel or Sparks it will spin over continually, as it will from stone cold.
Other than plugs, points timing, I cant think what's causing the fault.
Any ideas??
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Post by tonymark3 on Dec 20, 2020 17:06:32 GMT
I used to have a similar problem with my mark 1 many years ago. Always put it down to fuel evaporating in line and float bowl. I am sure someone will give you a more definitive answer, as never ( so far) had problem with the Mark 3.
Tony S
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Post by dave1800 on Dec 21, 2020 11:22:34 GMT
This can be difficult to resolve. In theory the Mk1 cars that have an electric fuel pump should be less prone to vapour lock which is the likely cause. It is important to ensure all the ignition and cooling components are in good order. If the car starts if you leave it for 10-15 minutes before trying to restart it this probably confirms vapour lock. It is important that the float chamber is clean and that the nylon jet tube is not gummed up which can trap vapour bubbles. Check the routing of the fuel pipe and ensure the heat reflector is in place. Sometimes pushing the choke in and out quickly a few times can dislodge bubbles in the nylon pipe.
One thing that is sometimes overlooked is that a slightly retarded ignition timing, a weak mixture or partially blocked waterways can increase the under bonnet heat sufficiently to cause the fuel in the float chamber to vaporise. This is an issue brought on by unleaded fuel and was not an generally issue in the UK with leaded fuel although in hotter climates such as India B series engines were plagued by ho starting issues and this was also reported in J2/J4 vans in the UK where there was little air circulation around the enclosed engine.
Perhaps a small electric fan on a timer cooling the carb when the engine is turned off could be an answer to prevent the heat soak?
David
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Post by jeff on Dec 21, 2020 14:41:27 GMT
Thanks for all that Dave, it makes sense.
The problem has developed into an intermittent misfire. I think there are cumulative problems. I've put new plugs in today which eased the misfire for a while.
On a road test an occasional stumble was felt, particularly after slowing down and then trying to pick up in 3rd gear.
I've reset the points, they were a bit wide, retimed, and freed off the vacuum advance which was a bit sticky.
No signs of arcing in the dizzy,
All I can do now is replace the silicone plug leads, condenser rotor arm and cap.
I had this problem with an MGB but never really cured the hesitation.
For good measure, I've also checked compressions. All four are equal at about 110psi.
Something is breaking down and I'm not convinced new replacement ignition parts are always as good as they used to be.
Difficult to solve when multiple symtoms appear at different times.
Once I've gone through the ignition and replaced everything, I'll turn my attention to fuel etc. Btw, there is no heat shield, just new braided hoses.
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Post by Penguin45 on Dec 21, 2020 18:07:19 GMT
Condensers cause all sorts of problems, especially modern ones. Get a couple from THE DISTRIBUTOR DOCTOR. Chris. |
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Post by jeff on Dec 21, 2020 18:41:17 GMT
Thanks chris, I've asked Tony Wood from LOCI to send all the kit. In the past it proved decent stuff so hopefully, so will this.
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Post by paddymk2 on Dec 26, 2020 20:08:59 GMT
Hi Jeff I had a similar issue with my mark 2. I'm wondering could it be the ignition coil failing when hot?
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Post by dave1800 on Dec 27, 2020 1:27:21 GMT
Quite possible, easy to check with a spare coil but my money is still on a fuel vapour lock, well documented on MGB forums. The under bonnet temperature rises significantly when the engine is turned of especially around the manifold. David Edit: Have a look at this MGB thread, post no 7 and 15 MAY provide an answer here |
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Post by jeff on Dec 27, 2020 13:58:30 GMT
Thanks for all that. The MK1 never did have a heat shield fitted. But I've altered the route of the flexible line to the carb a little, so it doesn't run along the line of the manifolds.
I'm currently waiting for all new ignition items, including the nasty little silk cotton earth wire in the distributor.
I have a couple of the old black cap ignition coils to experiment with. The one fitted is a Lucas gold.
I have an ongoing fault still to cure in another thread.
Thanks all
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Post by tonymark3 on Dec 27, 2020 15:00:34 GMT
Re ignition coils. I ordered one of these Bosch coils and would recommend them as has performed really well. Via eBay .I note the MGB lads not keen on the modern Lucas versions but I only have the original 1972 coil to compare. Still works but can you trust it?
 47F34FB9-33DF-4A08-A822-939C70CF9EB8 by Anthony Surman, on Flickr Tony S |
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Post by jeff on Dec 27, 2020 17:58:57 GMT
Yes good idea. I've also read somewhere that the modern Lucas coils are not keenly rated.the old ones I have are donkey's years old raided from scrappers in my youth.
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Post by Penguin45 on Dec 27, 2020 18:27:29 GMT
There have been a few discussions about modern Lucas stuff. Basically, it isn't Lucas anymore. I've got to the stage that if it's in a green box I won't buy it.
Chris.
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Post by jeff on Dec 27, 2020 21:22:18 GMT
Yes Chris, im heading that way. A lot of new "replica so called Lucas" stuff is sweat shop rubbish including point condensers and worst of all rotor arms. I'm glad I kept old stuff which was changed routinely 40 years ago.
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Post by paddymk2 on Dec 28, 2020 1:29:31 GMT
Which is a pity because there was a lot of great work (and community) inside that institution which was Lucas!  |
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Post by jeff on Dec 28, 2020 11:22:42 GMT
The big lucas factory in Birmingham employed half our neighbourhood when I was a kid.
The Lord Byron pub close by was a good stamping ground. Even Ozzie Osbourne worked there for a while, testing horns.
An eight hour shift of that would have driven me senseless. I was happy just fixing the buses.
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