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Backfire on overrun

Posted: Sun Sep 08, 2019 3:12 pm
by James k
Hi,
I'm getting quite a lot of backfire on overrun, for example when going down a fairly steep hill in third gear. What could be the cause of this and is it typical? I am talking about popping and not the classic Morris Minor overrun noise or exhaust parp.

Thanks,
James

Re: Backfire on overrun

Posted: Sun Sep 08, 2019 4:54 pm
by Myrtles Man
Leak in exhaust?

Re: Backfire on overrun

Posted: Sun Sep 08, 2019 6:18 pm
by mobylette
0

Re: Backfire on overrun

Posted: Sun Sep 08, 2019 6:18 pm
by mobylette
+1 for exhaust leak. Cast an eye over the entire exhaust system and see if you can spot any witness marks to show where exhaust gases are escaping , usually at a joint.

Re: Backfire on overrun

Posted: Mon Sep 09, 2019 9:56 am
by kennatt
check the timing probably slightly retarded

Re: Backfire on overrun

Posted: Mon Sep 09, 2019 11:23 am
by myoldjalopy
It could be any number of things in addition to those mentioned above - faulty plugs, wrongly set points gap, failing condensor, weak fuel mixture, sticking valves......to mention just a few. Are all leads and connections on the ignition system secure? Have you altered/adjusted/changed anything recently - which might be a clue?

Re: Backfire on overrun

Posted: Tue Sep 10, 2019 1:06 pm
by James k
Hi,
Thanks for the replies. I did change the head gasket a few months ago so the exhaust has been disturbed. I'll check the joints. The ignition and fuel systems have been checked over recently and are all in order.

Thanks,
James