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

[Bleyseng]

So many possibilities but, lube the dizzy advance weights as maybe the advance is sticking.

[Ansbacher]

Are the carbs jetted correctly? Possibly your main jets are too small?

Ansbacher

[dt4]

Are the carbs jetted correctly? Possibly your main jets are too small?

Ansbacher

This was Dylan (chi-towns) car so as far as I know, yes

[dt4]

So many possibilities but, lube the dizzy advance weights as maybe the advance is sticking.

I’ll look it up in my Haynes manual
I guess it’s in here?

[Tdskip]

I know it drove OK for Dylan when it was here, but that was sometime ago.

Fuel, air, spark with an eye on anything that has changed.

I’d start with spark as suggested.

[rhodyguy]

IDF carbs? Size? The interior of that distr is pretty dirty.

[dt4]

IDF carbs? Size? The interior of that distr is pretty dirty.

I shall have to get more involved in how these things work, I don't know how the distributor mounts or how the rotor arm is removed. Ill spend some time reading the Haynes manual and then start with the plugs and work towards the coil.

Are there adjustable points on these?

thanks

[dt4]

ps
No idea on the carb type / size etc...
I'll add a photo and see if any one recognises them

[Tdskip]

Carbs will have a stamping, which can be hard to see, on the main body in the middle.

https://www.carburetion.com/CarbID/weberID.htm

[dt4]

Pictures on the carbs

[rhodyguy]

That helps. Judging by that intake to carb gasket, those carbs have been on a long time. As mentioned, lots of possibilities. Not relevant, but where does that black wire on the + terminal go to? The line coming off the distr vacuum canister too.

[Tdskip]

You need to be very careful about not changing multiple things at the same time, but one easy test to rule out vacuum leaks given the condition of those gaskets is to carefully spray carb cleaner or starting fluid at the base of the carburetors while the car is idling.

That is probably the easiest test to do, perhaps do that before changing anything else.

I will bet a pint on it being electrical but a bad vacuum leak could present similar issues

[rhodyguy]

NOT ether. Spraying them down will compound the mess. It will drip muck everywhere. Just plan on getting new gaskets, spend some time cleaning the engine compartment and be done with that aspect. I wonder what flavor of distr is installed?

[Tdskip]

NOT ether. Spraying them down will compound the mess. It will drip muck everywhere. Just plan on getting new gaskets, spend some time cleaning the engine compartment and be done with that aspect. I wonder what flavor of distr is installed?

Hmmmm - but it will determine if he has vacuum leaks as an issue. Not saying the gaskets don’t need to be replaced but if he doesn’t have leaks that at least tells us there are other causes. No?

[Rob-O]

IDF carbs? Size? The interior of that distr is pretty dirty.

I shall have to get more involved in how these things work, I don't know how the distributor mounts or how the rotor arm is removed. Ill spend some time reading the Haynes manual and then start with the plugs and work towards the coil.

Are there adjustable points on these?

thanks

Looks like an electronic ignition module of some sort is installed. That little black box just under the rotor looks like a pickup for a Pertronix style ignition. Also can see a red and black wire tucked in under the rotor as well. Those would go to the pickup of the ignition.

So no points or condenser in there. But as mentioned the advance plates might be gummed up. But you’d probably feel that in all gears and anytime you stomped the accelerator.

But as Kevin said, it looks dirty in the distributor. Would t hurt to clean it. You can check the advance plates while you’re cleaning the distributor. Rotor just pulls off (pull it straight up).

[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.

[ejm]

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

3500 rpm should be around 45mph in 3rd and close to 60 in fourth.. any chance your clutch is slipping?

[dt4]

That helps. Judging by that intake to carb gasket, those carbs have been on a long time. As mentioned, lots of possibilities. Not relevant, but where does that black wire on the + terminal go to? The line coming off the distr vacuum canister too.

The black wire from the +ve terminal goes to the starter motor
The rest of the set up looks like this