Help needed asap

[VivaHCmark]

Long story short, car broke down the other morning, kangarooing so assumed carb jet blocked etc stripped, cleaned and while I was there, put my accuspark on.....now the car is back running, but I can't get a steady idle, it's like it's cammed or something similar, timing mark is where Haynes is saying, bang middle of the timing mark on case with vac off

The carb is a Weber 34ich....no amount of adjustment sorts the idle??

[1972nail]

First of all, check for air leaks around the carb and manifold. Make sure all bolts are tight. Make sure the vacuum advance pipe is not leaking air too. I've little experience of the Zenith carb itself but are you sure all the air and fuel ways in the carb are clear? I'm not just talking about the jets but the small passages in the carb body that supply the jets.

Now your Accuspark. Did you bypass the resistance wire in the loom and fit a 12V coil?

viewtopic.php?f=12&t=22328&hilit=bypass

Did you make sure that the distributor base plate earth wire was in good condition? Have you timed you ignition with a good timing light? Are you sure your plug leads are fitted in the correct order and in good condition?

Some people have reported that the Accuspark needs a couple of extra degrees of advance or retard to get it to run at it's best. I suppose it's probably all to do with manufacturing tolerances in the original distributor. If all the above are correct or have been fixed and they haven't cured the problem then add or subtract a couple of degrees and see if smooths out any. Don't go wild, just 2 or 3 degrees or so.

[VivaHCmark]

It's a Weber 34ich

I've checked all the usuals, you say about earth wire from baseplate in dizzy? I have no earth in my dizzy? Could that be my problem?

[1972nail]

It's a Weber 34ich

I've checked all the usuals, you say about earth wire from baseplate in dizzy? I have no earth in my dizzy? Could that be my problem?

The Accuspark needs a good earth through the baseplate for the Hall sensor inside to function properly. In theory so does a set of points but they are far more tolerant. The earth wire is a short black wire with two open ended spades attached to screws, one on the condenser securing screw and the other on the screw for clip for the cap.

[Fred Dukes]

Lesson if something is not working fix it 1st and make sure that you have cured the problem THEN fit your electronic ignition

[VivaHCmark]

well there is no problem with the electronic ignition, thats all working perfectly, gonna add an earth later this afternoon as i do have a slight miss on half throttle when cruising...carb is going to come back off, be stripped bare and cleaned again...can only assume one of the jets is still blocked, or possibly the idle circuit has some crud in it. just setting it up when its been stripped is a pain

car has never ran correctly since ive owned it, only had a slight miss to it

[glenn]

Hi, I've just joined the club even though I don't own a Viva, and haven't owned one - a 1975 1256 HC -since 1982.

I was browsing around the forum and noticed a lot of 'misfire' and 'starting/running problem' type posts. This was symptomatic of the 1256 HC way back when .. I owned one and several of my friends owned similar models. The fault -back then - was usually attributable to the distributor which was the achilles heel of the HC.

If you remove the rotor arm you should see a felt pad. The idea was to put a few drops of oil onto the felt pad on a weekly basis. The oil would trickle down and lubricate the distributor bearing, though most owners were either unaware of this - or didn't bother. Failure to do this quite often .. and I mean often .. led to bigger problems.

A 'sticking' distributor can cause starting and misfiring/running problems. The first thing to do when checking is to remove the cap, mark the position of the distributor, and then remove it from the block.

Measure the contact breaker gap on each lobe of the shaft. I think .. think .. the gap was supposed to be 13-15 thou?

Measuring the gap on each lobe gives you an idea of wear on the distributor bearing/shaft. Whilst one lobe may have a gap of 14 though, the opposite lobe could have a gap of 18 thou. This indicates the bearing is worn/sticking as it spins which can cause all manner of starting, idling and running problems. When a gap becomes 20 thou - a severe 'kangarooing' misfire occurs. The points simply aren't opening and closing as they should.

Next, spin the distributor drive by hand. If it feels notchy or gritty it tends to indicate a sticking/worn bearing. The distributor should actually feel smooth and easy to spin by hand.

The big danger here is that a sticking/worn distributor bearing can lead to bigger problems. The pencil-thick shaft that drives the distributor is driven by the oil pump in the sump. A sticking distributor bearing can seize - this causes the drive from the oil pump to twist and snap. Repair entails removing the engine, then the sump ..

This was a regular occurrence on Viva HCs in the late 70s and early 80s
The 'achilles heel' of the HC.

Whilst the distributor is off the car, dismantle it and look at the advance and retard mechanism below the plate. It's an easy job. The sliding plates and/or weights can stick, preventing the ignition from advancing or retarding as it is supposed to. Usually, the advance and retard mechanism needed little more than a spray with wd40 and a wipe clean. Also clean the inside of the distributor itself and make sure that the lead on the condenser has a good earth.

The distributor was the achilles heel of the HC - particularly the lack of lubrication on that little felt pad underneath the rotor cap.. When I think back to the late 70s and early 80s, I can remember having to strip at least two engines on HCs belonging to friends simply because the distributor had seized.

There were two types of distributor fitted to the HC - one had an offset drive.