1975 1.8 on twin carbs running poorly Options

[dt4]

My car is now registered over in the UK so I can enjoy it at long last, I took it out today for the first time other than the short drive to the MOT centre last month

It drove OK to a point but I noticed it was very slow to respond once in 4th gear, it felt very flat and not at all keen to pick up speed
If I shifted from 3rd to 4th at around 30mph / 3500rpm it was sluggish and a just over 30mph in 4th it felt like it was in the wrong gear and needed to down shift back to 3rd

on the hills it soon ran out of grunt and I was having to down shift from 4th to 3rd and even 2nd to get it to rev again and build speed
Setting off on a hill I had to really increase revs in 1st before shifting into 2nd otherwise it would bog down and feel like it was stalling

thoughts:
fuel?
timing?
other?

thank you
David

[dt4]

thanks for the input and suggestions chaps, I'll work through them and also feedback on the questions asked and provide a couple of photos of the ignition set up etc....

[porschetub]

thanks for the input and suggestions chaps, I'll work through them and also feedback on the questions asked and provide a couple of photos of the ignition set up etc....

If you set the engine to #1 cylinder with the rotor pointing close to the notch on the distributor body you can unbolt it by undoing it via the 8mm stud on the case,that way you will keep your current timing location,if you are lined up with your TDC mark on the cooling fan it will only go together one way.
When you have it out remove the small "C" clip on the vacuum advance control rod and remove the canister,you can then spray brake cleaner in and around the top advance assembly and keep moving it back and forward to free it up ,this may take a few attempts because you get a build up of crap between the 2 sliding faces.
once you have it moving freely spray some lube in there as well as removing the felt wick from the shaft under the rotor and put a few drops of engine oil in there.
Next test your vacuum advance before refitting the unit,it should hold vacuum by sucking on the hose and if the hose is dodgy replace it,replace unit and check the advance plate snaps the top advance plate back quickly when vacuum is released .
If not functioning in this way the vacuum to the canister will be overcome by friction and a full teardown of the dizzy will be required,the above method has about a 70% rate of success from my experience.
IMO because the car has been sitting for a while the carbs are most likely in need of a rebuild due to old fuel and crap built up over the years,which with Dellorto carbs is fairly easy to do and plenty of info online.
The above procedure may not cure your issue but it is something that needs to be done on a 40+yr old unit as many on here have found out,these Bosch units are prone to this issue,assuming your ignition is up to scratch and your timing and valves are ok you should be fine,good luck.