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Triumph TR3 - Stalling Issues

A friend of mine, Bill Elsing in PA. is having issues with the engine stalling.
Scenario is:
Starts fine, after 10 miles it runs rough and then stalls. Rest for 2 mins, starts up again fine. Drives a mile or less and it stalls again. This is repeated a few times until he reaches home and puts it away in disgust. Out comes the Vodka Tonic, without the tonic!

He has checked the tank for debris and cleaned it out. He has rebuilt the fuel pump, set the floats at 7/16th's and installed grose jets. All openings are clean and clear. All the lines are clear. He has a secondary in line fuel filter in the correct direction. Fuel is plentiful to the carbs. Plugs are sooty black on the outside and light tan at the center. Not having seen them myself, I am not sure to what degree of each.

My last recommendation was to richen the mix by two flats, backing it back to one flat if the first two flats resolves the issue. If it runs better with two flats then return it to that setting.

Anyone out there have any other ideas or resolutions, or even a confirmation of my recommendation. He could sure use the answer before the driving season is over.

Does your friend have a pertronix electronic ignition installed? This pattern is classic for an overheating electronic ignition module. If he has this type of ignition, he can solve the problem by changing to an electronic ignition which has the electronics module mounted outside the distributor, where it won't overheat.

Al Christopher
A R Christopher

Or change back to points, which I have never had a problem with. I like to tinker anyway.

My advice did not help him. Yes he does now have a Petronix system , but this was installed after the issues started as a possible solution. At idle the car runs very smooth and until the first 10 miles its fine. Then a bogg down effect and a misfire and the issues starts. Once it has sat for a few moments rest, it will fire right up. A mile or so and it happens again. I am afraid I have run out of ideas. If the issue was electrical, it would appear way sooner than 10 miles. Cap, Rotor, Plugs, Wires and Coil are all new. Any ideas anyone?

Can it be vapour lock caused by the 10% ethanol that it added to fuel in USA ? I had this problem when I was driving in the USA. See the thread below. My float bowls were empty and it sputtered like I was running on only 2 cylinders. Also I seemed to be out of gas. I was !!!

My float bowls were empty.

How are his float bowls when it happens ? Tell him to take off the tops and see if they have gas - or if they are empty.
Don Elliott

Maybe a plugged tank vent tube?

I am not familiar with the Petronix system, but I think the condenser is no longer there with the Petronix conversion, right? otherwise, I would have suspected the condenser. They can be good when cold, and fail with rising temperature, and recover again when temperature lowers.
I have also seen on a Spitfire, the ignition wire going to the coil was broken inside the insulation. Wires were touching and making contact, but with the heat, the "junction" became resistive and the engine lost ignition. This was the 4 inches piece of wire going out of the harness and connecting to the coil. Nothing could be seen from the outside of the wire, except a softer spot when twisting the wire.
Jean Louis Lafont

M. LaFont probably has a good idea there, although who would ever expect a forty year old piece of wire operating in an extremely hostile environment to ever have a problem? Addressing the float bowl idea, try checking the float lever height in the SU carbs, (if you have SU's)
Al Christopher
A R Christopher

I have the exact same problem, and have done the same, new electronic ign., fuel pump. It has to be vapor lock. Jean Louis has made a beautiful heat shield, I will try to duplicate. I am using about 1/2 aviation gas and it has gotten worse. My hat is off to Jean Louis, very good job.

Mark, thank you for this compliment. As I said to Don Elliott in another thread, I will take more pictures in 2 weeks when I am back home, and will mail them to him. I will also make a sized sketch for easier reproduction. If you are interested, send me your email to
Jean Louis Lafont

I think I found my problem. clogged fuel line at the tank. Have not had time to test but I could hardly get any air through it.had to run a wire through it just to break it up then blew it out with compressed air. I am thinking I better drain the tank using the bigger drain plug and see if any other stuff is in there. The tank was clean when I put it in. Now I will have time to make that heat shield from Jean Louis.

And the answer is: (drum roll) Ready for this? A clogged vent pipe inside the tank. Unbeknown to all it seems there is a 1/4" tube that acts as a trap, fixed to the inside of the tank, on the upper side behind (passenger compartment)the fill hole and is routed to the outside vent. This tube prevents gas from flowing out of the tank via the vent pipe. The previous owner had done a DIY job of cleaning, etching and sealing the tank and it seemed to have clogged this tube. So as the fuel in the line was used it caused a vacum lock and the engine/carbs died of fuel starvation. Simple when you think of it. I guess it would have worked if he had driven around with the fuel cap open. So who would have "thunked" it?

This thread was discussed between 03/08/2007 and 29/08/2007

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