My guess is that it isn't vapour lock - that's much more likely to happen when the car is stationary and there isn't a flow of air to cool the intake system.
Sounds to me much more like fuel starvation, which could be down to an ineffective fuel pump, partially blocked fuel filter or carb, although I can't think of any good reason why it should be worse when it is a warm day. Another random thought - coil over-heating? But again can't see why this would be worse at speed, or particularly when going up hills. So not too likely. Sorry I can't be more definitive... Richard On 19 July 2010 05:31, Greg Stull <gas...@roadrunner.com> wrote: > Hello, > > I have been having problems with my Spitfire sputtering like it's running > out > of gas above 50 mph on hot days after it runs for a while at that speed > especially going up hill. If you let up and drop down in speed it runs > fine. > Also runs fine at lower speeds even when it's hot. Runs alright above 50 > mph > when the temperature is cooler. > > I have a Weber carb with a mechanical fuel pump with the factory heat > shield > under the carb. > > Anybody have any ideas? Fuel filter, fuel pump, carb, vapor lock? Can vapor > lock happen at higher speeds? > > I'm going to start with new fuel filters. > > Thanks for any ideas. > > Greg > 1978 Spitfire 1500 > _______________________________________________ > > Spitfires@autox.team.net > Donate: http://www.team.net/donate.html > Suggested annual donation $11.47 > Archive: http://www.team.net/archive > Forums: http://www.team.net/forums > Unsubscribe/Manage: > http://autox.team.net/mailman/options/spitfires/rbgosl...@googlemail.com _______________________________________________ Spitfires@autox.team.net Donate: http://www.team.net/donate.html Suggested annual donation $11.47 Archive: http://www.team.net/archive Forums: http://www.team.net/forums Unsubscribe/Manage: http://autox.team.net/mailman/options/spitfires/arch...@jab.org