popping while freewheeling

its still popping while free wheeling ,i have noticed that if i pull the choke out it stops is it a carb problem ?, if i buy a new one to fit does it come ready to put on or do i have to fart about with it please advise best cure please, it runs fine otherwise

The carb leans out the mixture when freewheeling which means that the mixture doesn't alway burn completely before the exhaust valve open so it's still expanding and hence the pops

Your distributor should have a vacuum advance pipe that fires the sparks earlier on overrun to overcome this.

Other things that can cause this
- mixture or idle speed not set right on carb
- leak in inlet manifold or carb
- vacuum advance not working (test by sucking on tube)
- timing too retarded.

Mine pops a bit on overrun as I've had to knock the timing back but it doesn't bother me too much. Gives people a chance to hear me coming down all these steep hills, a good thing with series brakes!

why are you freewheeling?

I think he means on the overrun

are yu sure?

No, of course not and nor are you. Plenty of people think overrun and freewheeling are the same thing though.

chill, man! - the OP said "freewheeling" that was what I was querying. if and when he replies then we will all know. I suggest that accepting what the OP actually typed is possibly better than assuming he meant something different, dont you?

The Mad Hat Man said:

chill, man! - the OP said "freewheeling" that was what I was querying. if and when he replies then we will all know. I suggest that accepting what the OP actually typed is possibly better than assuming he meant something different, dont you?

Click to expand...

freewheeling - freewheelingb - definition of freewheelingb by the Free Online Dictionary, Thesaurus and Encyclopedia.. Heedless of consequences; carefree.

Sorry if that came across as me being agro - wasn't meant.

My reason for the (possibly incorrect) assumption for what he says is that I've been going through a lot of this stuff already this month due to my project. On this forum there have been many questions about popping on _overrun_, many more on other forums that I've seen recently and plenty of people getting the terms wrong.

If its popping when freewheeling, idling or overrun then it would be good if the OP come back and said which. Though the diagnosis and likely cures will be pretty similar. Freewheeling not a sensible idea though.

i.e. check mixture, vacuum leaks and timing.

will we every know. yes answer is likely to be similar.

my post was really to intimate that freewheeling isnt recomended.

If he's freewheeling the engine is idling, otherwise it would be over-running!

The ignition timing seems to be slightly to be too advanced, so try retarding it a bit.

i mean when going a long in top gear i take my foot of the\throttle to slow down this is when it pops put if i pull the choke out it stops it hope that helps you both

Sound as though you are running rich and possibly too far advanced.

lean I would have thought if choke cures it...

Try retarding your ignition a touch. also have you set the mixture on your carburettor properly?

running week or a hole or leak in the exhaust front pipe timing retarded leak in inlet manifold