4 hours ago
Reading Tony's thread about a sudden change in the way an engine runs, I thought I would share this in case it helps others...
Over the last two or three years, several of my cars after standing unused for many weeks in dry storage have exhibited a reluctance or downright refusal to run. In all but the latest case they were running fine when put away.
In all cases, a change of spark plugs effected an immediate cure.
In the latest episode, my MG VA suddenly ran rough as I was putting it into storage last November. Not having time to deal with it there and then, it was only last week that I got around to seeking what the problem was. Despite fully charged battery, fresh fuel, spark at the points and a decent spark on a removed plug, and applications of Easy Start, it refused to fire or run. I checked the SUs jets etc, all seemed fine.
I was scratching my head when I remembered there was a spare set of new plugs in the boot. Fitted them and the engine instantly fired and ran smoothly.
The removed plugs are standard, so I would expect zero resistance between top and electrode tip. Three showed no resistance, the fourth did. Whether this has any bearing on the refusal to fire at all, I do not know. Seems unlikely, but the ways of electrickery are mysterious.
As I say, having had this sort of thing now happen on several different vehicles and for a change of plugs to be the instant cure for non-start/rough running I cannot believe it is just coincidence. Maybe ethanol is at the root? Perhaps leaving a coating on the plugs if they are not used for a while?
Point of this is to say that from now on, unless something else is obvious, when an engine decides not to perform in some way, I shall always change the plugs first. Just to cover off that possibility.
I half-joked with friends that it might be that mainstream brands are manufacturing in China, with a possible reduction in quality. And then yesterday a replacement set of Bosch plugs arrived. Guess what...
20250303_121912.jpg (Size: 173.7 KB / Downloads: 56)
Over the last two or three years, several of my cars after standing unused for many weeks in dry storage have exhibited a reluctance or downright refusal to run. In all but the latest case they were running fine when put away.
In all cases, a change of spark plugs effected an immediate cure.
In the latest episode, my MG VA suddenly ran rough as I was putting it into storage last November. Not having time to deal with it there and then, it was only last week that I got around to seeking what the problem was. Despite fully charged battery, fresh fuel, spark at the points and a decent spark on a removed plug, and applications of Easy Start, it refused to fire or run. I checked the SUs jets etc, all seemed fine.
I was scratching my head when I remembered there was a spare set of new plugs in the boot. Fitted them and the engine instantly fired and ran smoothly.
The removed plugs are standard, so I would expect zero resistance between top and electrode tip. Three showed no resistance, the fourth did. Whether this has any bearing on the refusal to fire at all, I do not know. Seems unlikely, but the ways of electrickery are mysterious.
As I say, having had this sort of thing now happen on several different vehicles and for a change of plugs to be the instant cure for non-start/rough running I cannot believe it is just coincidence. Maybe ethanol is at the root? Perhaps leaving a coating on the plugs if they are not used for a while?
Point of this is to say that from now on, unless something else is obvious, when an engine decides not to perform in some way, I shall always change the plugs first. Just to cover off that possibility.
I half-joked with friends that it might be that mainstream brands are manufacturing in China, with a possible reduction in quality. And then yesterday a replacement set of Bosch plugs arrived. Guess what...
20250303_121912.jpg (Size: 173.7 KB / Downloads: 56)