Morris Minor Owners Club

Hi all

Have taken.Tilley for a bank holiday Sunday spin today. Just got back now.
All well to begin with other than the fact she has a yet to be diagnosed problem with the dynamo(see my previous post re that issue in electricl section) as there is a rattling noise under the bonnet. It isnt the fan belt btw, as previously suggested, as that is tight as a drum
However we can still drive her as we have been on a couple of trips max 10 miles without any issues.
However she began stuttering in 3rd and then in 2nd today On the return journey she was doing the same in 4th too.
Towards the end of our journey it was almost kangaroo style jumping.

Any ideas as to what may be causing this?

Many thanks
Maddie.

Can anyone offer any possible explanation for this please.

As you can imagine diagnosis from a distance is difficult, presumably petrol is fresh, and you can hear the pump ticking when you turn on the ignition. I’d guess it will be an electrical problem, look for good connections on coil and distributor, in fact in general. Check points, rotor arms can give trouble as can the condenser. These parts are not too expensive, if you do replace these things, do it one at a time, that way you’ll know what it was. However it might be elsewhere. Good luck.

" the fan belt btw, as previously suggested, as that is tight as a drum " I hope you are exaggerating. There should be a little slack on the belt so as not to strain the bearings. About 1/4 inch from memory.
As to your problem, it may be fuel vapourisation. When the temperature under the bonnet is high the fuel forms gasses in the system and may cause symptoms similar to the ones you describe. I fitted a home made stainless steel heat shield at the carburetter to manifold joint for many years because of this problem. However, I do not use it now.
As Les says, it is difficult to be accurate with diagnostics at a distance.

"About 1/4 inch from memory."
Without coming across as a smart Alec, the workshop manual recommends 1/2" (13mm) at the centre of the run between pulleys using moderate hand pressure.
"Tight as a drum", no. Not good for water pump and dynamo bearings.

As others have already said, reading you describing the fan belt as being 'tight as a drum' was like watching a contestant on a game show about to select the obvious wrong answer; my inner voice was screaming Nooooo

That could easily be contributing to a pulley or water pump bearing failure!
Different manuals for different cars recommend different amounts of slack; I can remember one car in my distant past (I've no recollection of which one) that used a technique of being able to get hold of the fan belt, mid way along it's longest section, and being able to twist it over 180 degrees between finger and thumb...
But whatever the method there has to be some slack or you're really asking for problems.

But your latest issue could be fuel vaporisation, you haven't mentioned what the pump sound was like... assuming you have a 'proper pump' and not one of those cheap constant running things.

In Maddie's other post about the dynamo we read "I think the dynamo is broken as there is a rattling noise under the bonnet when driving her and the ignition light is staying on."
The rattling could be dynamo bearings, but it would be better to more closely identify where the sound is coming from, rather than just 'under the bonnet'. Also, if the battery is not being charged (and it could be dynamo or control box issues), expect problems out on the road, especially if using lights, indicators, wipers etc.
As others have said, it could be a number of things causing problems but, at a distance, and without more information, we can only offer possibilities.

If the dynamo is not charging, low battery voltage can cause misfires, perhaps fix that first then look at the misfires.

Yes, that was my point really when I said "Also, if the battery is not being charged (and it could be dynamo or control box issues), expect problems out on the road, especially if using lights, indicators, wipers etc." It has happened to me - battery not being charged, car runs OK until using lights and then stuttering and increasingly conking out when stopping e.g. at a junction. Good thing I had a starting handle, because battery became too low to crank over engine........
I agree, get the charging issue fixed first, and then see how the car performs after that.

Thank you all for your replies.

So firstly you all had me laughing at my 'tight as a drum' analogy when referring to the fan belt. I was really trying to emphasise the fact that the fan belt was far from slack as I remember someone suggesting that a loose fan belt could be causing the rattling noise. It isnt as tight as a drum exactly as I do know it certainly shouldn't be but I've just been in the garage to check what a couple of you have said about 'play" measurement.
A quarter of and inch or even maybe half an inch from the middle? Well I really don't think it has that much give in it at all but my husband thinks it's fine. Is it possible for the rubber of the belt to shrink or tighten up if it hasn't been driven for a long time? as this has been the case until this Spring. I mean I'm talking 2 years standing, not out of choice believe me but due to circumstances that have only recently changed freeing up more time for us.
I'm feeling its a bit tight myself which would actually and possibly be the cause of resulting damage to the ball bearings in the dynamo.
Also someone mentioned was the fuel fresh. Well my husband has said there was old fuel in the bottom but he put fresh fuel into it. I'm wondering if this would contaminate the fresh fuel. Should we have drained out the old fuel first?
Car did also back fire once just as we arrived back home so loudly that I thought someone had been shot!
Hubby does think possible evaporation as it was a very hot day and we set off with half a tank of fuel.

I would appreciate your further comments.

Many thanks
Maddie.

OK....
Well the fan belt should be 1/2", so that sounds to be OK.

The fuel, well that depends of the ration of old to new when your hubby added the new.
Question though, did he manage to drive it to the garage to add the new fuel?
Or did he just get a can filled and bring it home?

Personally, with my car I've never suffered with vaporisation that I know of; I firmly believe an incident I had on Sunday was actually air being sucked in. See here for details: viewtopic.php?p=719208#p719208

My car's hesitancy was not in 'lower gears' it was under hard acceleration.

It would be good to get to the bottom of the Dynamo/rattling noise before worrying about hesitant acceleration.

Been blacklisted while at another ISP address, so now posting what I would have posted a couple of days, or so, ago.

Rather than ignition, I would suspect a fuelling issue - but I would be checking connections, all the same. Hard acceleration may show up fuelling problems which settle down on a more even run at lower throttle.

if it ran low on fuel there is a good chance it's drawn in some debris, there is a gauze filter on the lank inlet which can be cleared by blowing back down the line from the pump, there are filters in the pump an I've also had the pipe beween the jet and carb bowl clogged, these all cause hestation.