Dhla Problems On 1.9 Gti Engine Experts Please

[Grahamrally 0]

I've got an issue with my twin carb setup on my 205. I'm after a bit of advise really as to common problems from anyone who is experienced.

I've got a twin 45 DHLA Dellorto setup on a 1.9 and one of the carbs if furiously overfueling on idle. It's a problem that has arisen and has gotten gradually worse in the last 6 months. It's not an idle screw adjustment problem or a jet issue as I've played with the screws to get the best idle and swapped the jets in each carb with no effect.

When you look through the carbs into the trumpets at what the fueling is doing on idle you can see a very noticeable difference in the amount of fuel from one to another, but is equal in the two chokes on the overfuelling carb. It's pooling up in the carb slowly killing the engine, but when you then burn it off by revving it, it is ok until it sits back on idle and pools up some more. It won't take more than about 30 seconds for the engine note to change and start dropping off because of it either.

I suspect something to do with the accelerator pump circuitry, but I'm not really sure what would cause this? Can you help? I need to clear or fix whatever is causing it fairly quickly.

 

Thanks,

Graham

[Baz 421]

Can anyone answer/add to this? Would be for my benefit too!

 

Graham what chokes/throats and jets do you run?

[taffycrook 2]

Sounds like the needle valve is leaking. This shows up under idle conditions more than others.

Check fuel pressure, as tuning it down to 3psi is often all that is required.

If pressure is correct swop the valves over if the problem moves to the other carb renew the needle valve.

 

Check the float heights as these can cause the same symptoms.

[Grahamrally 0]

The answer was to change the needle valves. They had been gradually getting blocked with some gasket sealant a friend used to seal the top covers a while ago!

 

Graham

[taffycrook 2]

Lucky guess!

[Grahamrally 0]

Lucky guess!