After a perfect run to this weekend's event, we had problems getting the our Bedford MW to run properly from the start of the return journey.
Several stops and a lot of head scratching showed that there was no spark on the front two plugs EXCEPT (and this is the nutty bit) when we held the plug cap in close proximity to the terminal of the spark plus.
The spark could be heard arcing from the inside of the plug cap to the nipple on the end of the plug, when this was happening the engine ran fine. However as soon as the cap was pushed onto the plug the engine ran rough as the plugs stopped sparking.
To get home we secured the two plug caps just off the plugs with wire so they could arc to the top of the plug.
So why would a spark plug fail to work when properly connected to the HT lead but work well when there is an arc between the plug cap and the plug?
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Bigjohn
After a perfect run to this weekend's event, we had problems getting the our Bedford MW to run properly from the start of the return journey.
Several stops and a lot of head scratching showed that there was no spark on the front two plugs EXCEPT (and this is the nutty bit) when we held the plug cap in close proximity to the terminal of the spark plus.
The spark could be heard arcing from the inside of the plug cap to the nipple on the end of the plug, when this was happening the engine ran fine. However as soon as the cap was pushed onto the plug the engine ran rough as the plugs stopped sparking.
To get home we secured the two plug caps just off the plugs with wire so they could arc to the top of the plug.
So why would a spark plug fail to work when properly connected to the HT lead but work well when there is an arc between the plug cap and the plug?
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