Tu3 With Lad Head & 28/36 Flat Spot

[Mid-life 205 0 1 Cars]

I have a 205 Rallye with a Kent PT 02 cam in a LAD head and a webber 28/36.

When driving there is a flat spot on the first choke, runs fine at full chat. When pulling away the revs dip into the flat spot and then you hit the throttle and it takes off. Impossible to drive about town. (not what I bought it for but you feel a bit dumb thrashing away from every set of lights at the age of 52)

 

I have cleaned the carb and blown through every hole I could find. No Change.

 

Put it on a timing light, steady on idle. It picks up to about 1500 revs and then all hell breaks loose with timing jumping. If you open up further it settles down again and you see the advance kick in.

 

Pulled the distributor off for a strip and inspection, both springs present and correct on the advance. Coil pack to distributor cable looks a bit rough but does not seem to fit the symptoms.

 

Has anyone seen a faulty distributor do this or is it more likely the wrong distributor advance curve.

 

Thoughts anyone?

[calvinhorse 870]

Try unplugging the vacuum advance pipe to see if that makes a difference, could also be a sticking float in the carb.

 

Could also be a bit of crap in the fuel jet, I had a hair size piece of wire wool stuck in a jet, you could still see past it but it caused mayhem in the engine

Edited December 12, 2016 by calvinhorse

[Mid-life 205 0 1 Cars]

Try unplugging the vacuum advance pipe to see if that makes a difference, could also be a sticking float in the carb.

 

Could also be a bit of crap in the fuel jet, I had a hair size piece of wire wool stuck in a jet, you could still see past it but it caused mayhem in the engine

I have already cleaned the carb and it is not flooding or running rich, so not the float valve. It is repeatable at the same revs every time, not unreliable or flaky.

The spark goes wild when it dies so it has to be on the distributor side?

I did read somewhere about the amplifier unit on the distributor causing similar problems so I may try that first. Just wondered if anyone else has seen anything similar?