Re: the backfiring problem. My kit car had such a problem some years ago based on a VW 1500 engine with bosch carb. Nothing helped that I did or my friend who was a competent auto mechanic did.
Finally reading some EAA material I realized the problem was that when I replaced the Oil air cleaner with a paper element filter it allowed the engine to draw too much air for the fuel it drew so it was way to lean. The remedy for me was that JCWhitney sold an adjustable main jet for that carb. Replacing the MAIN JET and making it easier to draw more fuel and balance the mixture cured my problem. Different carbs may well pose different problems but the solution could be similar. I hope you find as easy a solution Paul Mueller Now back to my original question about the backfiring/timing problem. Can anyone help with that? That's what I really need to have some information on. I'm sure others have encountered the same problem. How did they solve them? This is an 1835 cc. engine with single port heads firing one set of plugs on a slick mag and the other on Great Planes electronic ignition backfiring at idle to slow speeds. What's causing it? C'mon guys, chip in here if you will, I need some advice. Thanks, Neal Hornung lt1corve...@earthlink.net EarthLink Revolves Around You. ------------------------------ Message: 23 List-Post: krnet@list.krnet.org Date: Tue, 27 Apr 2010 17:56:23 -0400 From: "Dan Heath" <da...@windstream.net> Subject: RE: KR> Backfiring at idle/slow speeds To: <lt1corve...@earthlink.net>, "'KRnet'" <kr...@mylist.net> Message-ID: <001601cae654$7a82e340$6f88a9c0$@net> Content-Type: text/plain; charset="iso-8859-1" I am familiar with the engine as I have one in my shop that has since been converted to a 1915. Backfiring can be caused by running too lean, and probably by a timing that is too advanced. Your engine should run at the same, or nearly the same RPM, with either ignition, on and the other off. If it doesn't, one or both of them is not at the correct advance.
