Volkszone Forum banner

1965 beetle backfire on decelation / rev drop

372 Views 5 Replies 5 Participants Last post by  skoobay
I have a recently pucrhcased 1965 beetle and has porsche fan, twin webbers 40, 1741 engine with fuel pump and CSP Electronic Distributor Pacemaker Bluetooth.

BUT it is backfiring when hot(30 mins drive) on decelaration, ie rev drop? Probabaly can not fix myself but do like to know what I am asking for to be fixed!
Thanks for any replies....
1 - 6 of 6 Posts
I'm leaning towards your electronic distributor being at fault. The engine heat can cause issues. Buy/borrow a standard 009 with points/condenser. Retest it. You may need a standard coil too.
An exhaust leak can cause backfire as well.
Check for any air leaks around joints and head flanges.
Mine did this when there was a hole in the heat exchanger usually going down hill, was like a flame thrower
Often a hole or leaky joint in the exhaust system as above. Closely inspect it for any tell tale black sooty streak marks. Heat exchangers to silencers / headers is a common leaky point. Had this a few times in the past, I got to the point I could almost time the backfire exactly to make pedestrians jump especially when coming down hill. (Young & foolish days !)

Once you've ruled this easy one out then look deeper into things like distributors / carbs.

  • Haha
Reactions: 1
thnaks all - will check exhaust first....
1 - 6 of 6 Posts