Adjusting dellorto 40 on 126 engine

hi folks,

since the rules for the hill climbing trophy have changed and turbo isn't allowed anymore, i had to abandon my 126 turbo project and started to rebuild the engine. after some time, it is almost complete.

but i have a BIG problem with the carb. i have twin dellorto 40 dhla (+- same like weber 40, but italian made) and the original mechanic fuel pump. when i start the engine, it jumps on without problems, but RPM go to maximum immediately even without giving gas. the idle mixture screws are open only for 1 turn, so the mixture can't be very rich due to this setting. but how is it possible, that the RPM go to 5000 as soon as i start the engine?

has anyone of you some knowledge about using this carb on 126/500 engines? (it is very popular in italy and germany) should i try to decrease the amount of fuel floating into the carb? i really have no idea how to decrease the idle RPM to +- 1000.

THANK YOU FOR ANY HELPING INFORMATION.

Regards,
me+myself+my_fiat126

probably you have too big idle jet

write spec your carb

how big main jet + air corrector + idle jet + choke etc...

hello, i will check the dimensions and post it here during the weekend.
have a nice day!

hi,

the iddle jet is 58 and main jet is 145.

have a nice weekend!

main jet probably is good
idle is to big rather

to dual carbs you must have elektric fuel pomp,becouse elektric give you that presure what you need,but this i not your problem probably,,
if you can put here some fotos of your engine.

Hi, here is the image, but it is not very good - it was shot with my phone and the engine are is veeery dirty I will post some fresh images after I implement new smaller jets and wash the engine.

mechanical fuel pump is satisfactory for one carburattor

Hi Sasuke !

I try to help you...

So first, you must calculate all the elements size, with the engine capacity (600 cm3) and maxi rpm you use to go.

If your engine is 600 cm3 with 5000 RPM Max, you must have :

26 or 28 (max 30) for venturi
95 to 100 110 max) for main jet
7772.2 or .1 or .14 for emulsion tube
180 for air jet
50 for iddle jet
33 on pump jet

But could you tell us wich letter is neer the 40 DHLA...40 DHLA E ? 40 DHLA N ? 40 DHLA F ?



- Check the needle valve : is it tight ?

- Check the float level in hight position : 15 mm


And to finish, you can put mechanical or electrical gazoline pump. No matter ! But Dellorto DHLA carbs must be feed with 1,5 to 2,5 PSI ! No more ! And to regulate correctly this pressure, I advise you to put a FILTER KING regulator !
Personally, I let the original mecanical pump and I've got Filter king. It's perfect !


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Nation of good man is univers

[ wiadomość edytowana przez: ilcubopiccolo dnia 2007-07-03 11:36:46 ]