TR4/4A 1964 Triumph TR4 - Not Starting/Running

[jrev77]

1964 Triumph TR4
Dual Zenith Stromberg Carbs

Hello,

I purchased a TR4 this past spring that drove well on the test drive. I got the car home and after doing
some brake work, took the car for a test drive, but it would stumble and stall. I removed both carbs and
noticed both floats were cracked, and there was sediment in the float bowls. There was also some leaking
fuel around the edge of the fuel pump.

I started by draining the fuel from the tank. I replaced the fuel pump with a stock, OEM mechanical fuel
pump and installed an inline fuel filter. The fuel filter is located after the fuel pump, before the
carburetors. I replaced the floats, O-rings, float bowl needle valves, float bowl gaskets, and cleaned the
carbs. I replaced and gapped a new set of sparkplugs.

I centered the jets, baselined the jet adjustments screws 3 turns from the bridge per the workshop
repair manual. I baselined the idle 1.5 turns after the idle screw makes contact. I adjusted the float
height to 18.5 mm per the workshop manual.

After these initial adjustments, the car started after cranking multiple times (lots of times) and ran well
for 5 minutes after turning the idle down a little.

A couple days later, I attempted to start the car and it would not start again. While trying to start the
car, it would run for a second or two, then die. I checked the spark plugs and noticed they were wet and
replaced them with a new set. I’ve verified that the fuel pressure is correct at 2.5 psi. The front carb
(closest to the grill) is now leaking fuel out of the front vent hole and fuel is backing up to the vacuum
advance. (distributor) The car will not start as-is.

The car did come to me with the battery set up as a negative ground. (I thought a 1964 would come from the factory with a positive ground) The coil looks relatively new (Lucas Sport DLB105), the positive on the coil (white wire with a black stripe) is hooked up to the coil. Is this correct? Could it cause starting issues?

- Without the car running, is there a way to verify if the car is not getting enough fuel or flooding
the engine?
- Is there anything else you would look at to get the car running?
- We did not touch anything related to timing, but could that potentially be causing any of our
issues?

 

[NutmegCT]

Interesting that the car ran well on its first drive. Maybe the distributor shaft worked loose while driving, causing timing problems.

If the plugs are wet, I'd say there's a spark problem. Remove a plug with its wire attached, turn ignition on, wear a glove and hold plug near cylinder head, and crank engine. See if there's a continual, repeated, spark.

And if fuel is backing up at the carbs, if fuel pressure is correct, I'd think the floats are set incorrectly.

Timing could certainly be an issue: fuel/air gets to cylinder but spark occurs at the wrong time. (Note reference above to possible loose distributor.)

Check one thing at a time, and let us know what you find.

And ... welcome to BCF!
Tom M.

 

[Geo Hahn]

The white/black wire from the coil to the distributor should be on whichever coil post conforms with ground... in your case the negative post.

Sounds like something is stuck open on the front carb... most likely the little valve. You want to clean them thoroughly when new lest there be anything on them that might make them stick. The action needs to be very free as there is not a lot of force applied by the float.

Not original but I replaced the screws holding the bowls with socket head cap screws... much easier to do and undo than when using a little flat-head screwdriver.

Hopes this helps but also a good time to verify everything... points gap, rotor advance, etc. Generally, ignition causes more running issues than carbs.

 

[Sarastro]

I answered this on the other forum, but I'll do it one more time.

You have wet fuel on the plugs, fuel leaking out of the carb vents. The problem is staring you in the face! Fix the carbs, and I'm sure all will be well.