JJC Posted May 30, 2019 Report Share Posted May 30, 2019 Long story (there’s a post way back) but in short what it’s doing now is starting, running on 4, blip throttle, backfires both ends, back carb starts flooding. In getting to where we are everything obvious has been tried and everything that could go wrong has. yes there is fuel, yes there is spark, no the timing isn’t out. Yes I have replaced the float chamber jets. Yes the carbs were set up properly. Yes the plugs were replaced and are not faulty (unlike the previous set of new plugs). It’s a mystery and it’s getting on my nerves Thank goodness the 6 works JJC Quote Link to post Share on other sites
Lebro Posted May 30, 2019 Report Share Posted May 30, 2019 If one of the carbs is flooding then: 1) float level set too high 2) needle valve leaking 3) fuel pump pressure too high causing 2 above Bob. Quote Link to post Share on other sites
JJC Posted May 30, 2019 Author Report Share Posted May 30, 2019 Bob might be 1 but unlikely as float level checked when fitting new valve. Why does it wait until after backfire to start flooding? If 2 then new valve supplier will get an earful, but see 1 above. 3 it’s a TR4 I should be so lucky! But if it was, front carb would suffer. Current plan is carb dismantle. JJC Quote Link to post Share on other sites
Geko Posted May 31, 2019 Report Share Posted May 31, 2019 It backfires because it is flooded and fuel is building up in the venturi, it usually starts at the rear carb. Check if the oil level in the dampers is correct (engine oil Ok) Quote Link to post Share on other sites
ctc77965o Posted May 31, 2019 Report Share Posted May 31, 2019 There's something wrong with the carburettor. Quote Link to post Share on other sites
Z320 Posted May 31, 2019 Report Share Posted May 31, 2019 The new float valve has the same diameter as the old one? Quote Link to post Share on other sites
stillp Posted May 31, 2019 Report Share Posted May 31, 2019 Swap the float valves between the two carbs to see if the problem moves. Pete Quote Link to post Share on other sites
Andy303 Posted May 31, 2019 Report Share Posted May 31, 2019 (edited) Still using the original plastic floats? Perhaps one is damaged and a switch to the "stay up" nylophyl type may be in order. Also, what type of float needle are you using? Edited May 31, 2019 by Andy303 Quote Link to post Share on other sites
JJC Posted June 2, 2019 Author Report Share Posted June 2, 2019 Yes, the thought suggested to me is to compare the weights of the floats. They look like original floats so might be past it. What’s really annoying is that I paid to have the carbs rebuilt when I put the car back together. JJC Quote Link to post Share on other sites
JJC Posted June 4, 2019 Author Report Share Posted June 4, 2019 Would you believe it? New Grose jet faulty. I really am fed up with this. JJC Quote Link to post Share on other sites
Lebro Posted June 4, 2019 Report Share Posted June 4, 2019 (edited) I prefer the viton tipped SU float valves. Bob. Edited June 4, 2019 by Lebro Quote Link to post Share on other sites
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