[TR] Rough Running TR4

[Randall]

---- pbrandsema at triad.rr.com wrote: 
> I have a pertronix igniter installed (past 10 years)
> with no problems there. Could these fail?

Not common, but it happens.  What does your timing light show?  Another crude test is to remove a plug, reconnect the wire and lay the plug on the rocker cover while you crank the engine with the key on.  Should get a nice fat spark, visible even in sunlight.  If it's puny or hard to see, might point towards an ignition problem.

Just on general principles, I would also check the spark plug wires for end-to-end resistance (cap terminal to plug terminal).  Many modern spark plug wires do not work well with the insulation-piercing terminals used in the original Lucas caps.  They sometimes fail internally while looking fine from the outside.

>  I'm getting some gas, but how can I tell if I'm getting
> enough?

The definitive test would be to connect a fuel pressure gauge so you can read it while driving.  But since you are seeing the problem at idle, it should be good enough to disconnect the line and direct it into a jar or can while cranking the engine.  If you see a strong pulsing action (the original pump only works on every other engine revolution), then it probably isn't a fuel delivery problem.

What happens if you give it a bit of choke?

Randall