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Morris Minor issues.
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john-saab



Joined: 06 Dec 2007
Posts: 341
Location: West Dorset

PostPosted: Wed Jun 29, 2011 3:14 pm    Post subject: Morris Minor issues. Reply with quote

I'm looking at my friends 1962 Morris Minor and it's baffling me.
It will start 99% of the time..will run for anything from 2-60 mins then will slowly lose power and stop. I thought it was a fuel issue, new points on the pump, cleaned the carb and it still does it...even if i pull fuel out of a can so then i looked at the electrics..i think thats where the problem is as it has now lost indicators and horn. The spark at the contact breakers is sometimes perfect then other times it's very weak. I replaced the breaker points. condensor, leads (nothing to do with this but they were here) and tried another coil..still the same issues. I have cleaned as many earth points as I could find and checked the engine to body earth strap. The wiring loom is in great condition as it was replaced about 6 years ago.
My thoughts are turning to the ignition switch..any other ideas much appreciated.
These cars ar supposed to be simple but this is confusing me.
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victor 101



Joined: 03 Apr 2009
Posts: 446
Location: East Yorkshire

PostPosted: Wed Jun 29, 2011 3:24 pm    Post subject: Reply with quote

Hi John, have you checked the fuses, I believe there are two, one for ign side and one for non ign items, pop the fuses and clean the terminals, including the spade connectors that connect to the fusebox.
regards Rod.
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Rick
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Joined: 27 Apr 2005
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Location: UK

PostPosted: Wed Jun 29, 2011 4:13 pm    Post subject: Reply with quote

At first I was thinking of pressure building up slowly in the tank (blocked breather/cap), but if it happens when running from a petrol can then it can't be that. I'd be inclined to try another electric pump on it, just in case it's wilting a bit after a period of use.

When it finally conks out, how long before it'll re-start?

RJ
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Jim.Walker



Joined: 27 Dec 2008
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Location: Chesterfield

PostPosted: Wed Jun 29, 2011 4:48 pm    Post subject: Reply with quote

Bad connections and switches will normally get hot under load - eventually hot enough to fail as an electrical conductor. Have you tried checking components/connections by touch for heat? Particularly the ignition switch.
Checking for voltage drop across every switch and connection is the proper way. Voltage drop should barely register on a 2v meter if ok. Don't forget that even things like the mounting of the distributor in the engine block is an electrical connection and can cause problems.
The voltage drop across the "load" (coil or motor or whatever) should be as near as possible to the loaded battery voltage. Say within 1/2 a volt. If not there is a bad connection somewhere.

Incidentally, If my memory seves me right the IGN fuse on a minor only carries ignition controlled accesories. The Ignition Circuit is unfused.
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Churchill Johnson



Joined: 11 Jan 2011
Posts: 359
Location: Rayleigh Essex

PostPosted: Wed Jun 29, 2011 9:41 pm    Post subject: Reply with quote

Have you given any thoughts about the exhaust system has any of this been replaced or repaired just before the loss of power problem,my father had a friend who years ago had fitted a repair pipe to the rear silencer of his old estate, but it was smaller then the original, result, lack of power, and i had a car in for repair that was showing the same symptoms, i had noticed that when opening the throttle with no air cleaner on that fuel was being ejected from! the carb on anything over half throttle, fault was a blocked rear box, then years later i obtained a rear box for my old cortina mk3 from a scrapyard after fitting it same thing, lack of power,and if it was badly blocked it would cause bad starting and even stop the eng.
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RobMoore



Joined: 16 Jan 2011
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Location: Peterlee

PostPosted: Wed Jun 29, 2011 11:36 pm    Post subject: Reply with quote

Check the earthing strap underneath the engine to chassis, take it off clean it and the area it attaches to.
do the same for the earth on the battery.
and if you still have the voltage regulator tope left of bulkhead looking from the front of the car, remove each spade connector and give them a clean with some emery cloth.
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Jim.Walker



Joined: 27 Dec 2008
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Location: Chesterfield

PostPosted: Thu Jun 30, 2011 10:15 am    Post subject: Reply with quote

RobMoore wrote:
Check the earthing strap underneath the engine to chassis, take it off clean it and the area it attaches to.
do the same for the earth on the battery.


If those connections can handle the starter load they are not going to stop the engine!
But the blocked exhaust is a possibility, if not very likely. It sounds very similar to the symptoms I had when some joker(?) shoved a potato up my tail pipe.
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john-saab



Joined: 06 Dec 2007
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PostPosted: Fri Jul 01, 2011 8:19 am    Post subject: Reply with quote

Thanks for your help all..i'm back on this today and i'm pretty sure it's not a potato up the exhaust..but i will look.
I'm going to continue with cleaning all of the terminals..i'm also going to try a 3rd coil..i know that's nothing to do with the indicators or horn but i'm clutching at straws now..apart from the ignition switch i have changed everything, cleaned everything, tested everything...i even checked for a blown head gasket..although the rear 2 cylinders were slightly lower than the front 2 the plugs are clean and they held pressure for a while so i'm sure that's not the issue. I have a spare voltage regulator..i will give that a go 1st!
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Rick
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PostPosted: Fri Jul 01, 2011 8:41 am    Post subject: Reply with quote

Is the replacement condensor a NOS item or a modern repro?

R
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Jim.Walker



Joined: 27 Dec 2008
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PostPosted: Fri Jul 01, 2011 11:13 am    Post subject: Reply with quote

Why not take a live straight from the battery to the coil? If the problem still exists you have at least ruled out the ignition switch etc. If it does cure it then the problem is still with the wiring or switch.
Either way you will have eliminated about half of the possibilities.
Jim.
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john-saab



Joined: 06 Dec 2007
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Location: West Dorset

PostPosted: Fri Jul 01, 2011 6:49 pm    Post subject: Reply with quote

Rick wrote:
Is the replacement condensor a NOS item or a modern repro?

R

NOS from my old stock pile..i replaced it because of this problem..i tried a differnt one aswell..no difference.
Jim..good idea! I didn't get the time i was hoping for on it today so will try a straight wire tomorrow..
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Jim.Walker



Joined: 27 Dec 2008
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PostPosted: Sat Jul 02, 2011 1:08 pm    Post subject: Reply with quote

A blocked exhaust does not necessarily involve potatoes! A detached baffle in the silencer can be the culprit. Though Morris Minors were mostly (if not all) originally fitted with Burgess type absorbtion silencers (straight through, with no baffles), which gave the charecteristic "wow" on deceleration. A baffle silencer might have been retro-fitted though.
Jim.
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Nic Jarman



Joined: 05 Oct 2008
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Location: Stoke by Clare, Suffolk

PostPosted: Tue Jul 05, 2011 10:33 pm    Post subject: Reply with quote

What do the plugs look like? If it is running rich it can peter out but it will be consistent.
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pigtin



Joined: 23 Nov 2007
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Location: Herne Bay

PostPosted: Tue Jul 05, 2011 10:54 pm    Post subject: Reply with quote

I had a similar problem with a Standard 8 a few years ago and I found it to be the flexible part of the fuel hose between the pump and the tank.
The hose did not leak fuel but was drawing in air. The MM has an electric fuel pump so it might show up by the pump racing.
I think a lot of fuel hose problems have been brought about by unleaded fuel.
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peter scott



Joined: 18 Dec 2007
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PostPosted: Thu Jul 28, 2011 8:03 pm    Post subject: Reply with quote

Possibly this...?

http://www.oldclassiccar.co.uk/forum/phpbb/phpBB2/viewtopic.php?t=8225&highlight=red+rotor
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