Ian Cooper Posted March 4 Report Share Posted March 4 Hi. 1970, Gt6 Mk2, standard CD 150s, electronic ignition, std 2ltr rebuilt 800 miles ago. The engine doesn't get much running and often takes three cranks to start but usually runs really well when started, however if I run along a dual carriageway (60ish) the engine will try to stall when I get to an exit roundabout, unless I keep the revs up. Keeping the revs up, will cause some high temperature readings, (not the dual carriageway running) but after a short time things will settle down and everything appears ok. She was running a little rich but I'm progressively winding the mixture back (1/4 turn a time) and she idles on the cool to normal side (Revotec fan) in the garage 7/800rpm. Any ideas where I can look to discourage the hot stalling please? Thanks Ian Link to comment Share on other sites More sharing options...
Pete Lewis Posted March 4 Report Share Posted March 4 (edited) get it to its best running mixture , if its rich ...its wrong if it stalls it will read higher temps. as the block heats the coolant thats now not circulating. same as when you switch off . wind the jet up till it falters the idle and richen 1/2 turn or set to best Pete Edited March 4 by Pete Lewis Link to comment Share on other sites More sharing options...
Iain T Posted March 4 Report Share Posted March 4 Also make sure you have enough damper oil. I use 20/50 engine oil and top up to half way up the filler. Don't overfill. Check for air leaks. My car used to stall if the mixture was too lean. Check there is slack in the throttle cable at idle and the throttles are returning to the stop screws not held on a short cable. I've done that! Link to comment Share on other sites More sharing options...
AlanT Posted March 7 Report Share Posted March 7 Is the heat shield that sits between the carbs and down pipe in place? I had a Spit missing this and it stuttered like mad when hot. Link to comment Share on other sites More sharing options...
Ian Cooper Posted March 7 Author Report Share Posted March 7 Hi. It's as standard, so no aftermarket heat shield. Link to comment Share on other sites More sharing options...
Gully Posted March 7 Report Share Posted March 7 If you've got your fuel mixtures correct, you may find you simply need to increase the idle speed slightly. In the 10+ years I've had my GT6, whatever I do to it, it will never idle happily below 900rpm! However, the only 'hot stalling' akin to your issues that I've ever had was down to the mixture being too rich. Gully Link to comment Share on other sites More sharing options...
GrahamB Posted March 7 Report Share Posted March 7 2 hours ago, Ian Cooper said: so no aftermarket heat shield. The heat shied is a standard part, part number UKC8372 Link to comment Share on other sites More sharing options...
GrahamB Posted March 7 Report Share Posted March 7 6 minutes ago, GrahamB said: The heat shied is a standard part, part number UKC8372 Sorry wrong car; I thought I was still on the Spitfire 1500 thread. Link to comment Share on other sites More sharing options...
Peter Truman Posted March 7 Report Share Posted March 7 I had serious running issues with the daughters Mk2 spit always stalling and running rough, the issue was the float bowl plastic insulator that locates the angle of the float bowl to vertical had failed ie broken with age allowing the bowl to swing towards the exhaust manifold hence the fuel vaporization and stalling! DIY heat shields made out of aluminum, can't find photos will post later Link to comment Share on other sites More sharing options...
Pete Lewis Posted March 8 Report Share Posted March 8 you need to correct the rich mixture before you mess about with shields and fans Pete Link to comment Share on other sites More sharing options...
Ian Cooper Posted March 8 Author Report Share Posted March 8 I'm still 'tweeking the mixture but the back three now look to be spot on and the front three are pretty close; looking at the plugs. Link to comment Share on other sites More sharing options...
Iain T Posted March 8 Report Share Posted March 8 2 hours ago, Ian Cooper said: I'm still 'tweeking the mixture but the back three now look to be spot on and the front three are pretty close; looking at the plugs. I prefer to measure first. I set both needle heights and jet depths with a vernier to within half a gnats c**k the same then mark the bottom adjusters so I know where both carbs are when adjusted on tuning. I also use a carb synchroniser to ensure the flow rate is the same. That way some of the variables are reduced and it's just down to mixture settings. Iain Link to comment Share on other sites More sharing options...
Ian Cooper Posted March 8 Author Report Share Posted March 8 Front and back three look bang on after my last tweek, and on a short run today no attempt to stall, fingers crossed😎 Link to comment Share on other sites More sharing options...
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