Triumph Repair: GT6 Mk3 troubles, fuel mixture, uk spec

Question
Hi,

I am having some trouble with my GT6 as when I get it up to 3000rpm, after about 5 or ten minutes it will lose power and just go along at 2000rpm and stay there. If I put my foot down it will either do nothing, or give a quick burst and then go back down again, and if I take my foot off the gas and then put it back down, it will do the same quick burst and then slow down again. If I pull over and turn the engine off and leave for a few minutes, it will be fine for a short time after and then do the same thing again. It doesn't misfire or make any bad noises, it just won't pull, and pulling the choke out makes no difference.

I don't think it is ignition related because I have had the distributor replaced and have got no problems with timing or spark. It is running on standard carbs ( UK spec ), the diapragms have been replaced and there is fuel in the glass bowl when I look after I have pulled over ( which is a lot ! ). My mechanic has said it could be the fuel pump or fuel vaporisation, and that it sounds to him as though the fuel mixture is too lean, although another enthusiast suggested it was too weak ! It idles fine and is great until it gives up, so any ideas you can offer would be much appreciated.

Many thanks,

  Tim

Answer
it does sound like a weak fuel pump. i had the glass fuel bowl on my JAG also. I disconnected it and put a regular filter in place of it.try that. the carbs on the gt6 didn't have mixtures that were adjustable enough to get you into trouble so i don't think it is there.as for vaporisation it usually cuts the engine all the way off.have you modified the exhaust system ? that can effect it too. i had a iginition problem once sort of like that but i really think the filter or pump is causing it. let me know. Dave