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What's Going On Here Then? - South African Manta A Problem


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Hi All.

I've got myself an interesting problem here.

Car's a '75 Manta A Automatic with stock 1.9 and Solex still on.

A little recent history of the car; About 3 months ago it started stalling for "no reason". Never any problems starting and would rev fine, but about a minute later would just stall, whether I'd gotten under way or was still sitting in Park or Neutral. After a bit of poking and prodding both by myself and my mechanics we diagnosed carb needed rebuilding (the state of some of the gaskets was appalling), had to import a rebuild kit (but that's besides the point) and eventually that was done.

Car now idles beautifully and revs cleanly (Better than ever I would say.) However, I can't get up to 80km/h (50Mph) even on flat ground. I get this horrible/quite violent jerking back and forth. Stamping on the accelerator just makes it kick-down and do the same but louder (higher revs). Happens at lower speeds on hills (even slight ones) and sometimes when cold.

I've gone from thinking it's fueling to distributor/timing and now I'm thinking maybe the gearbox. <- I feel I should point out that none of these have actually been ruled out.

I'm declaring myself officially out of ideas, so I'm looking for some from someone else :P.

Help, please? And major thanks for any advice in advance.

Edited by Binnacle-ZA
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  • 4 weeks later...

Oh Lordy, I have no idea what's been happening.

So; News since last post. Car no longer starts.

I decided that things weren't progressing at my mechanics and hired a trailer to bring it home. Had it back a couple of days now and today I decided to check for a few things (Weathers been atrocious, so haven't had a chance).

First thing I did was adjust the float slightly as petrol was pouring through the barrels (sorted).

Then I'd been suspecting is that the primary and secondary jets were swapped when the carb was rebuilt. (done, no change)

Did my head in for an hour or two before deciding, "you know what, let's check that there's a spark" so after turning a couple of rooms upside down looking for my plug spanner I got back under the bonnet, pulled the plug aaaaannnnnnd... Completely black with carbon. (These had been new and put in when the carb was rebuilt.)

Wedged it on top of the rocker cover, and nothing. Some contact cleaner, a small file and some sand paper, not much in the way of progress.

Then I remember I've got a spare (old) set I swapped out about a year or 2 ago. Hook it up, wedge it again and Dun-da-da-da: spark-spark-sparkedy-spark.

Hmmmm... swap them all out and joy of joys, good strong life for the first time in about 4 months.

So... Turn off and turn on again to make sure it will restart, just in case something happens on the now planned test drive. And off I go, onto the main road... No problems; got up to 100km/h, no jerking on hills.

So 2 things;

  1. Can someone tell me what would cause such bad carbon build up on the plugs. (They did seem to have a smaller gap than the old ones.)
  2. Someone that still has their Solex confirm where/what your jets are just in case I'm wrong (I can't remember what mine are at the moment. Will post mine here soonish, either when I find my notebook or decide to reopen the carb.)

Thanks everyone.

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Its possible that with the jets being the wrong way round, it was over fueling and flooded pretty much straight away. If its been started up and not run, or just turned over for long periods of time it will never fire untill the build up of cack on the plugs has been removed. (I had a honda civic that did that, wouldnt run at all untill all plugs removed and cleaned!)

Glad you've got it sorted, hope it lasts that way

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  • 9 months later...

It's happening again... :( So sorry for a bit of a Necro-post but it is the same thing (I think).

As an update, the Auto has been dumped for a 5-Speed.

And since the last calamity everything has been perfect, except the choke worked itself loose a month or so ago, that was soon fixed.

So last Saturday the Manta wouldn't start while I was out and about, turns out the little brass pipe that goes from the top of the carb into the bowl had worked loose, sorted I thought. And then I ran out of petrol, at least I think I did as I was extremely low on it, I could start the car and drive fine, but as soon as I let off the power/came to a stop it'd die. Always restarted, and I managed to go like that to the nearest petrol station. Filled up. And then it wouldn't idle, started and revved fine, but anything under about 1200/1300 rpm and dead. Opened up the top of the carb and gave it a blast of carb-cleaner, no help. Started fiddling with things (Stupidly). No help, settled for screwing the throttle stop to idle at about 1500 to get home.

Got home.

Next day, wouldn't start (I suspect I buggered it up at the petrol station). Gave the carb a thorough cleaning (went through about 2 litres of cleaner). No go. Reset all needles/adjustment things to "default," a new set of plugs, aaand Bingo. Idles beautifully, revs cleanly and was pleased as punch.

Until I got out on the road as a test run. Then the same as way above, ie. sudden nosediving/jerking, dies then picks up over and over, until complete loss of engine power (doesn't matter what you are doing with your foot).

Now there are a couple of things I can add to the info.

  • It's not rev related (I'm pretty sure) as I can get right to the red line in 1st and 2nd, but usually in 3rd or 4th, somewhere between 3800 and 4500 revs it starts doing it's thing. One time I pulled over and popped the air cleaner, didn't see anything amiss, but then wouldn't start, re-popped the air cleaner and the secondary was happily dribbling away, flooding it. Adjusted the float a little and got it started, still did the "thing" on the way home.
  • The felt under the dizzy rotor arm is quite dry. (Am I correct in thinking this should be lightly *soaked* in engine oil? what about the little felt wiper on the points/cam?)
  • I've got some blow-by (crankcase pressure), just adding info, don't think it's directly related. As it does "it" with ventilation system connected and removed.

My current thoughts on the matter: It's either too much petrol, throwing the sparks dead, or too little and it's starving. I lean more to the flooding at speed, can the mechanical pump on a CIH overpower the float at higher revs?

Opinions please! Very much appreciated in advance.

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I'm a novice so please forgive me if this sounds stupid, but my car was doing some funny things when the condenser was breaking down.

Ah, hadn't actually thought of that (So it wasn't stupid). I've got another one floating around somewhere, will see if that changes anything.

Will probably go hunt for a fresh cap, rotor, condenser, points, leads and a backup set of plugs this week coming.

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I had lots of problem with points on my A series so changes to one of those electronic ones that fits under the cap.

Something like this.


After getting one of these i never had any problems with the points or cap again.

Also just another thought. Right at the back of the fuel line mine user to have a bit of rubber hose that connected from the fuel lines down to the tank. That had a split and use to suck in air and cause problems starting if left for a day or two and i use to think it was the carb drying up. it never leaked but i only found it while looking for something else that was causing a problem on the tank float. Just a thought!


Edited by 611
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Practically dismantled the dizzy yesterday. cleaned everything, lightly lubed it up and swapped the condenser for one I found in the boxes of parts off my wrecked car. The replaced condenser was slightly bulged at the back and didn't pass "the ohm test."

Now running OK.

But I must have put the points out slightly as there's very little "get-up-and-go" untill about 4k OR I've leaned out the mix too much as the temperature is a little up. There's a whistling sound if you plant your foot.

Either way, seems the condenser was at fault. I've ordered a new cap, rotor, cond. and points anyway. Going to have to wait 2 weeks or so for all of it, must be the last ones in South Africa :P, amazed they even have the Manta on the books still.

Cant you put a bosch one on it? Im sure i have a spare one somewhere in the loft.


Yes, I could if I can find one. I'm not too keen on what shipping it from the UK would cost (Although it was a kind offer, so thank you). and I'm looking to go injection some time in the near future anyway, so will use the electronic dizzy from there when that happens.

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Nice work. And no problem on the offer. Shame its so expensive to send as in distributor lees on mine now so wont need the bosch one as a spare for mine!

At least you know what's causing the problems. i use to spend a lot of time adjusting the points on mine. They seems to have a mind of their own :-)


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