SanRod

Hi again, replaced plug and coil leads and all connectors.. Multi spark is gone. Discovered coil to distributor low tension wire nearly broken, only a few strands left holding at the distributor end so has been replaced. Spark at the plugs while cranking as suggested above is yellow white but not sure it is of the "fat" variety were looking for. Also discovered the bolt holding the distributor clamp bracket to the cylinder head was loose and tightened up, clamp bolt is secure. Still no joy and can't even get it to run How does one determine that the coil is getting the voltage it requires as mentioned above ? Bit of a grey area for me I've never been able to grasp the intracacies of electrical goings on very well just not my forte!! The distributor cap is an old original type with side exit leads and I have suspected this from the beginning but it's one of the more expensive options to replace. Earlier when I could get it to run I observed it in the dark and could see no signs of tracking on the outside at least.. As a side check there is fuel to the carburettor and it was running ok previously. The plugs appear to be slightly wet when removed so am assuming fuel is getting thru to the cylinders. In respect to Tortrons comment above re the distributor body being loose on the shaft I'm not sure what to look for there, do I need to remove distributor to check that out ? Frustrating !!!!

Thanks for the comments everyone, good feed back. I have been working on a process of elimination in order of cost and based on your comments I will upgrade the leads as is being suggested and go from there. They are old and would look better even if it doesn't run haha. I will post again after that and advise how it went. Dizy cap could be next after that if no success with leads

Plugs are new and after only a few Kms look only slightly blackened an wet with unburnt fuel cos they're not firing

Hi as a newbie please forgive me for the following rant about our misfire but I love a challenge and hate having to give in to a mechanic !! Our 1936 Morris 8 has a serious misfire. When we purchased it a few months ago and took for a test drive all was fine but soon after we got it home it suddenly lost a lot of power (and there wasn't a lot to start with!!) during a wee outing and barely made it back to base. We were told by the seller and noted at purchase that it had new spark plugs, coil and coil to distributor HT suppression lead with a "spitfire multi spark" some sort of inline voltage booster in this lead(see image) Think there might have been a clue in all that but we missed it. Investigation of the misfire revealed that it was not firing on 3 & 4. After a bit of trial and error found that by swapping out plugs 3 & 4 for a couple of spares the problem disappeared. Armed with that knowledge we elected to try a complete new set of plugs figuring that perhaps the relatively new ones that came with the car were faulty. I had nagging doubts that this was the problem but it seemed a relatively cheap fix. The original NGK B6HS were replaced with Champion L82Cs and off we went runnin pretty good. A couple of short runs around local roads went fine but then Lo and behold suddenly the misfire was back and investigation revealed number 4 plug misfiring. Refitted an original NGKs to 4 and it came right again but soon after the problem was back. While # 4 was misfiring I tried moving the plug to other cylinders and the misfire moved with the plug which made me think it's not the distributor cap leads or rotor or mechanical or fuel related ( compression is fine) Replaced the condenser ... no change. Swapped out coil HT lead and booster for an old school wire one ... No change. Plug and contact breaker gaps are set to hand book specifications Distributor to plug HT leads are wire type and appear sound The car at some point in the past has been converted from 6 to 12 Volts and I note from research on the interweb that the NGK B6HS plugs are correct for the model/year which would have been 6 volts. Is some one able to tell me if the 12volt coil/condenser combination plus multi spark thingy is simply too much for plugs perhaps designed for a 6 volt system and somehow frying them prematurely? I'm reluctant to purchase different plugs of any sort without knowing if this is the problem and how to address it. Look forward to some feed back cheers Rod.