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</o:shapelayout></xml><![endif]--></head><body lang=EN-CA link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I had a similar problem while racing. I thought it was carbs but they were Ok, I checked timing it too was OK. What it turned out to be was fuel starvation under acceleration once I got up to speed. I found a tiny kink in the fuel line and problem was solved. Check for this and also check the fuel pump to make sure its delivering maximum fuel and not crapping out on you.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Larry<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span lang=EN-US style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span lang=EN-US style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Healeys [mailto:healeys-bounces@autox.team.net] <b>On Behalf Of </b>John Spaur<br><b>Sent:</b> Friday, January 29, 2021 9:49 AM<br><b>To:</b> 'Bob Spidell'; healeys@autox.team.net<br><b>Subject:</b> Re: [Healeys] Another backfiring question<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I use a Uni-Sync too but I also used a hose when I recently installed new HS4 tricarbs. The hose works well too but it does not give you an indication of air volume, just equal noise.<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>John<o:p></o:p></span></p><p class=MsoNormal><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif"'>From:</span></b><span lang=EN-US style='font-size:11.0pt;font-family:"Calibri","sans-serif"'> Healeys [mailto:healeys-bounces@autox.team.net] <b>On Behalf Of </b>Bob Spidell<br><b>Sent:</b> Friday, January 29, 2021 8:18 AM<br><b>To:</b> healeys@autox.team.net<br><b>Subject:</b> Re: [Healeys] Another backfiring question<o:p></o:p></span></p></div></div><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p><p class=MsoNormal style='margin-bottom:12.0pt'><span lang=EN-US>I dunno if it can cause high RPM backfiring (I think it could), but the airflow on all (2-3) carbs has to be the same--or, at least, very close--at all throttle positions. This has to be checked off-idle, obviously, but if it's good at, say, 2,500RPM it should be good at all speeds; if not, you have to disconnect the throttle connect shaft to set them. I suppose a crack Brit-car mechanic can test with the recommended 'hose-in-the-ear' technique--my ear hose is collecting dust somewhere--but I use a Uni-Syn.<br><br>To paraphrase the TV commercial we've all (probably) seen a thousand times: "If you don't have a carburettor synchronizer, get one."<br><br>Bob<o:p></o:p></span></p><div><p class=MsoNormal><span lang=EN-US>On 1/29/2021 6:13 AM, healeyguy--- via Healeys wrote:<o:p></o:p></span></p></div><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><div><div><div id=yiv9115048286><div><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black'>Len and Listers<o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black'>Pushing the pin up to lift the piston is the start of the "test the mixture setting" exercise. You begin the push, ever so slightly, and listen to the idling engine. The idle goes up. What do you do next? You continue to raise the pin to see what happens. If the idle continues to rise you know you are in a rich condition. If the idle stops going up and starts to drop off the mixture is pretty close. If the idle does not increase from the start you usually assume you are in a lean condition. This gets the carb mixture close at idle which in theory means the carb is going to operate throughout the RPM range. <o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black'>There is one other assumption here, that being that the carbs is in the same condition as new mounted on an engine operating as new. That is when allot of other stuff comes into play. The carb float bowl items, needle/seat and float level must be set correctly. Float must not be leaking thus making it sink. Carb must have the correct main needle and jet and they have to be installed and adjusted correctly. Flutter at high RPM may indicate that the piston spring in the suction chamber is weak or the incorrect spring installed. Ignition timing and condition and setting of ignition points.<o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black'>The list goes on and on......<o:p></o:p></span></p></div><div><p class=MsoNormal style='margin-bottom:12.0pt'><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black'>P<o:p></o:p></span></p><div><p class=MsoNormal style='margin-bottom:12.0pt'><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black'>-----Original Message-----<br>From: Leonard Berkowitz <a href="mailto:DrBerkowitz@hotmail.com"><DrBerkowitz@hotmail.com></a><br>Subject: [Healeys] Another backfiring question<o:p></o:p></span></p><div id=yiv9115048286yqt58392><div id=yiv9115048286><div><div><p class=MsoNormal><span lang=EN-US style='font-family:"Calibri","sans-serif";color:black'>Hi all<o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US style='font-family:"Calibri","sans-serif";color:black'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US style='font-family:"Calibri","sans-serif";color:black'>Just finished repairing and reinstalling the carburetors on my BJ7. I thought I had everything adjusted properly. According to my Haynes Manuel the engine speed should increase slightly when you lift the piston a very small amount. Mine does that. My dwell angle is where it needs to be and the car starts and idles nicely. Also sounds beautiful when I punch the accelerator linkages. The problem is that when I get it up to 60-70 mph I get what sounds like backfiring into my carburetors. Also sounds like it doesn’t have a whole lot left in the tank, so to speak. Does that sound like I am running too rich or too lean? <o:p></o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US style='font-family:"Calibri","sans-serif";color:black'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span lang=EN-US style='font-family:"Calibri","sans-serif";color:black'>Len Berkowitz <o:p></o:p></span></p></div></div></div></div><p class=MsoNormal style='margin-bottom:12.0pt'><span lang=EN-US style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black'><o:p> </o:p></span></p></div></div></div></div></div><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p></blockquote><p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p></div></body></html>