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TR2/3/3A Backfire!

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tinman58

tinman58

Jedi Knight
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Why does my TR3 backfire at start up? (only from cold). After one POW it will fire up and warm up nice...
 
The gas is never old. (I drive the car all the time). Could it be when I pull the choke it lets to much in ? I have the moss supercharger with the SU HD8 carb.
 
If an engine backfires when cold, it's usually because the mixture is too lean.
 
What we called a backfire was caused by shutting off your ignition and turning it back on - resulting in a loud BANG from the tailpipe, always good for scaring pedestrians. There should be another term for the spitting back through the carburetor which is what you meant when you used the word backfire. What do our British cousins call the two? Anybody know?
 
I am sure it is the supercharger. Take it off and give it to me! I have power envy.
Check the plugs for color burn?
Jerry
 
So if I take off the supercharger and give it to you, that will solve the backfire problem?
 
Well Dan, If I have the supercharger, I will be so excited, I won't care about your problem. But I do agree with above on a lean mixture. I would check the plugs first.
Jerry
 
Thanks Guys! I will check the plugs.
P.s. The "backfire" blows out the pop off valve on the intake manifold.
 
Sorry Jerry! I was already to remove the supercharger and ship it to you, when I saw the post on being to lean. I richened the carb a bit and no more backfire (or sneeze) She fired up nice.
Sorry Jerry.
 
Darn,
Well, I am working on a mini now 1968. So I guess I don't want to take the TR3A apart again anyway. I can't wait to try the mini in an autocross!
Jerry
 
So is there an actual term for a backfire into the carbs, different than backfire? I've always just called them both backfiring even though they're actually distinct symptoms. (Backfiring out of the tailpipe is a whole lot better than setting the foam on your air filter on fire, ask me how i know....)
 
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