a couple of problems with my new twin dcoe setup

[gt_owner]

hi all,
have been rather busy this month with putting a few new things onto my car,
one of which is the twin dcoes, i have a couple of problems,
firstly it seems i cant get enough movement from my cable linkage to open the buterflies the entire way, its a sytec twin cable linkage has anyone used these before?
second problem i seem to get quite a bit of fuel leaking from the throat closest to the firewall but all other three are okay, could this mean there is somesort of problem with this cyliner not fireing?
and finally it seems to cough and spit when i increase the throttle?

im sure these all sound like the same annoying questions that all newbies ask but any suggestions that anyone could offer up would be very greatly apreciated,

[gt_owner]

i should mention my jet sizes i guess

choke 30
sec venturi 6
main 120
emulsion f47
air 130
idle 57f21
pump 35

[europatek]

Fuel leaking from the throat is quite often the needle valves not seating properly and flooding the float bowl. Take off the cover, remove the needle and make sure all is clean. Gently blow them off.
Basic setup starting point:-

- make sure you have used thackery washers and they are tightened correctly.
- make sure the soft mounts are in good shape - no air leaks.
- balance the carbs. I take out the two inner blanking screws for the progression holes and shine a lead light up the throats. You can see the butterflies. Adjust as needed.
- screw all the idle mixture screws in to seat and then back out 2 -2.5 turns as a start.

The above should get you well on the way. Once running adjust mixture screws as needed and then the speed screws. Now you should be able to drive it and start the jetting side of things.

Sounds like you need a bigger air jet - say 180. Idle I would say 45F9 or 50F9 as a start.
I'll ceck my weber book for the F47. Not sure about 57F21. As far as I know weber jets are all increments of 5.

[gt_owner]

oh cool this will give me a few things to get tinkering on, i might buy some new jets then so as i can have a swap around of them will probabaly change like you suggest
the emulsion to f16
air to 180
idle to 50 f9
pump to 40

still not sure i can get enough movement out of the linkage to make the butterflies turn right around though

[ski 65]

Don't know if you have the same set up as mine but I had to bend the adjusting rod that fits between the linkage that connects the two carbs together and the linkage that joins up to the cable attachment. I'll try and post photos tomorrow. I actually replaced the brass rod with a piece of 3/16" threaded rod from Bunnings. Only downside is you lose the left hand, right hand threads for quick adjustment. Photos of your setup might help.

Cheers

[ski 65]

This is what I mean...

[gt_owner]

hey thanks ski
that is pretty much the same setup as mine i will post a few pics of mine tomorrow,
would you be able to post a picture of where the block secures the cables to the pedal,

cheers

[gt_owner]

okay so i have changed as follows

choke 30
sec venturi 6
emulsion to f16
air to 180
idle to 50 f9
pump to 40
main 120
needle valve 175

still getting the same issues
what other causes would there be to fuel leaking from the carby throats as changing the needle with a brand new one has not fixed this?

still running the same also, coughing and backfireing , the carbs are set up on softmounts so i tightened them just a fraction more hopeing to fix any possible air leaks but this has not helped

as far as the linkage goes im getting a mate to make up a bar to connect to my pedal so as i can get more adjustment there as soon as he has done that i will get pictures of it up here

[lotus]

Have you checked the height of the Floats, if they are not set right fuel will overflow out of the hole to the lower left of the front face of the carb.

[nomad]

Check the float(s), it is not unknown that they leak causing excessive fuel in the bowl (see the post above) just one more of the minor aggravations of which to be aware.