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Here's an east test to validate proper spark plug ignition, with the vehicle running you can pull off a single plug wire (spark plug end, while wearing a thick glove) and see pay attention to the Engine RPM's drop. You shoud be able to tell by the audible change in the engine speed and noise. Replace the wire to the plug and repeat for the other 3. If one wire when removed doesn't cause a change the RPM , you've narrowed it down to that single electrical path or cylinder. Could be the plug, Could be the wire, could be the dist cap. Simply switching the spark plug wire and retesting as metioned above can help you determine what it is. i.e. does the problem move w/ the wire or stay w/ the cylinder.
A compession test could also determine if there is a burnt or sticky exhaust valve.
The ignigtion of raw fuel in the exhaust could be from the normally functioning other cylinders.
Many years back as kids we used to turn off the ignition while still driving my '69 bronco (No steering lock & usually in front of a buddies house late at night) and then place the key back into the run position.. LOUD BANG as planned !!!! quite impressive until I split a cast iron exhaust manifold and the ruptured the muffler... Who was laughing now!!
Just to back up another posters mention to look at ignition system, I tried to trace a stumbling issue in my bronco , rebuilt the carb, no luck, turned out it was the NEW Napa Dist cap. Changed back to the prior one and the problem went away..
Here's a cool , well written book on automotive design, function and theory, it's not a repair manual and it's not my auction....
I was given the same book as a kid and still refer to it today from time to time. What's cool is that all the systems in your rover are essentially covered in this easy to read and follow book. I think it's basically a Highschool automotive shop text book. The rover is so basic the automotive fundementals apply to it.
Good luck... Talbot
A compession test could also determine if there is a burnt or sticky exhaust valve.
The ignigtion of raw fuel in the exhaust could be from the normally functioning other cylinders.
Many years back as kids we used to turn off the ignition while still driving my '69 bronco (No steering lock & usually in front of a buddies house late at night) and then place the key back into the run position.. LOUD BANG as planned !!!! quite impressive until I split a cast iron exhaust manifold and the ruptured the muffler... Who was laughing now!!
Just to back up another posters mention to look at ignition system, I tried to trace a stumbling issue in my bronco , rebuilt the carb, no luck, turned out it was the NEW Napa Dist cap. Changed back to the prior one and the problem went away..
Here's a cool , well written book on automotive design, function and theory, it's not a repair manual and it's not my auction....
I was given the same book as a kid and still refer to it today from time to time. What's cool is that all the systems in your rover are essentially covered in this easy to read and follow book. I think it's basically a Highschool automotive shop text book. The rover is so basic the automotive fundementals apply to it.
Good luck... Talbot
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