Rods 'n' Sods - UK Hot Rod & Street Rod Forums banner

1 - 12 of 12 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter · #1 ·
I am new to forums, and i have a problem ....
I have had a single 45 weber on a lynx manifold for quite sometime now all bought from new, fitting it to a 2.0 Pinto engine in my Mk3 Cortina.
I have been experimenting with jettings for ages and ages and i have come close to getting it right when the engine is warm, but starting from cold it runs like abag of nails and im getting petrol running out of the barrels.
I think the problem lies qith the float settings, idle jets and/or needle valve ?
Does anyone have any cloe of a Base setting for a single 45 on 2.0 Pinto .... there is plenty of advice for dual carbs but Nothinig for single use, i have des hamills book and david vizard but neither go into great detail on float settings.
I'm at a loss, someone please help me.
Thanks for your time,
Dan

Oh current settings are
Idle jets that have worked in the past but not quite right
F2 65
F11 65
F8 65
F9 65
I think i'm right with the 65 as decreasing makes idle even worse.

Needle valve 200
Float shut off - 14mm (but have tried 7.5mm through to 15mm
Float droop - 26mm

Em tube F16
45 Aux Venturi
36 Chokes
50 Pump valve

As for mains and air corrector i cant remember what they are but i figure they are ok as the problems lie within the idling section?
 

·
Banned
Joined
·
4,329 Posts
Up the pressure of the regulator to 4-6 psi. I havent played with these carbs for over 20 years but you may be getting "venturi back spill" or what is called fuel overload on start up.A phenominum called "needle bounce" can also occur if the line pressure is too low. It might be worth checking to see if the spring on the needle valve is also in tact if the carb has been apart. You can go down to a 32 mm choke on this carb depending on cam as too large a choke can also cause cold start fuel wash.
Failing that im stumped!
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #5 ·
I'll try and up the pressure see what happens. Which spring are you talking about on the needle valve, the ball bearing?
 

·
Banned
Joined
·
4,329 Posts
Depending on the year it was manufactured some side draughts had a spring fitted over the needle valve. Run the ignition timing at 12 degrees at 1000 rpm and dont use the vac advance and at 3000 rpm dont go over 36 degrees advance. I cant remember a lynx manifold but the shorter it is the less the fuel atomises at low revs.
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #7 ·
i upped the pressure and still no joy, i altered the float level setting againhigher and lower but i get alot of engine rocking and fuel coming out of barrels, just cant figure whats going on. can anyone enlighten me on needle valve size and float settings for this kind of setup?
 

·
Delinquent in denial...
Joined
·
583 Posts
Twin DCOEs like around 3.5psi fuel pressure, could be the same for a single carb? I have an old Haynes Weber Carburretor manual which lists jet settings and just so happens to list a single 45 on a Pinto! For a 45 DCOE 13 they are:
Choke size 34mm
Auxiliary venturi 3.5
Main jet 1.45
Emulsion tube F2
Air corrector jet 1.85
Idle jet 0.55 F4
Accelerator pump jet 0.50
Accelerator pump inlet valve with exhaust orifice 0.50
Needle valve 2.25

I have the plastic floats in my 40s set at 13mm closed and 25mm open.

Hope this helps! :tup:

Matt
 

·
Banned
Joined
·
4,329 Posts
Check the floats for "submarining"

Take out and drop into a pan of water,if they sink they have a puncture,hold under the water and check for air bubbles,if bubbles are seen they are also punctured!
 

·
Off the Xmas card list
Joined
·
24,094 Posts
The last time I worked on an engine with a Lynx and 40 it did everything you are describing , fuel standoff at revs plus puddling . It needed a bigger cam to make it work.
 

·
Registered
Joined
·
5 Posts
Discussion Starter · #12 ·
Yeh, well i managed to get hold of a Weber haynes tec book and it gave me the required float settings for my particular carb, which was 6.5mm closed and 14mm open. So i changed that and had to alter all my other settings just to get it idling reasonably well, and yes, no more flooding and it seems to run very well indeed now. The setting i currently have are :-

36 chokes
4.5 Auxiliary venturis
145 mains
200 air corrector
65F8 idle jet
F2 emulsion tube
Float 6.5 closed 14 open (according to book)
200 needle valve

Ive ordered som 34 chokes, and the book states that i should be using 3.5 Aux Vents but im having trouble finding those at the mo.
I thnk the next step is to take it to a rolling road to get it fine tuned.
 
1 - 12 of 12 Posts
Top