Villiers popping through exhaust.

Hi all,
I have a problem with 3 of my villiers engines now 2 x Mk 20 and Mk 12
I am getting a miss fire popping sound back through exhaust almost like a small backfire,
I have used different carbs, the valves have all been ground in and gaps checked, have checked
and double checked but no difference, any ideas that I could try, many thanks in anticipation.

Timing, tappet clearance?

Woodsman wrote:Timing, tappet clearance?

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timing should be 3/16" before tdc that is the piston not the flywheel,when piston is set 3/16" btdc set the flywheel timing marks to all line up
some will also for light work and displaying you can set all up to tdc but i dont go any less than 1/8" before tdc
i thinking its the timing as you will have done all of them and the flywheels are keyless and a sod to set up on your own
hope this helps
kev

Thanks Kev and Paul,

It was the last part that I got wrong ref setting flywheel to mark at 3/16 btc, I read somewhere to set points to correct gap
then it was 3/16 just as the points open, then I thought the marks were there to time at tdc.
All good now, well one is no time to take cowls off others yet.
Thanks again

Regards Richard

Now all running sweet, thanks again.

your welcome and now a qualified villiers timing tecnition
kev