sq4 solex-bi-starter

[chris.shearwood]

Have you checked for air leaks around the throttle spindle where it passes through the carb body?

[Chris Sealy]

For anyone interested; I have found that TePe [blue] interdental brushes, used with carb cleaner, will clean all jets and orifices in the 26 AHD except the pilot [70] which is too small, without causing damage.

[Henning G]

Hi, wow, those drawings really lighten things up for me. Now I can se the way air travels in idle, but where does the fuel come from, does it come from the emulation tube? My carb was renovated at a company called “carburetor hospital” and it seems that they have done a decent job, no play in the throttle axel, and the flange is straight as well. The rocker box is also new from Draganfly, so I think I have done what I could to have a nice tick over-BUT…THANKS a lot for all the help. I will check all my jets and maybe….

[simon.holyfield]

For anyone interested; I have found that TePe [blue] interdental brushes, used with carb cleaner, will clean all jets and orifices in the 26 AHD except the pilot [70] which is too small, without causing damage.

That's a great idea. I'll get some for the workshop.

[simon.holyfield]

Fuel flow path highlighted in orange. The fuel is coming upwards towards the pilot air bleed jet (crossing from the float bowl casting to the cover casting) before going into the blue path Pete showed us earlier.

[Henning G]

Hi Simon, THANKS a lot, now everything make sense. I have found out that my Air correction jet is 120, should be 150, and my pilot bleed is 150 ( don’t know if that’s correct) Main and pilot jet are correct. Haven’t managed to find the Bi-starter ( starter jet) and the Bi- starter (air-jet) Any idea where to bay new jets…
You have been most helpful…

[simon.holyfield]

No worries Henning.

My starter air jet, the one on the bi-starter casting is marked 11R-3; my starter jet (fuel) is marked GS 100.

I don't have any sources for bits, but I do know that these carbs were used on various small French & German cars (BMW, Citroen) in the 1930's & '40's, and some Stuart Turner engines. Could be a lead?

[chris.shearwood]

Any idea where to bay new jets…

I don't know if this company would have the jets you require but they may be able to point you in the right direction:
https://www.carburettorspecialists.com/

[Henning G]

Hi Chris and Simon,
That’s the very same company that overhauled the carb for nearly two years ago.. Thanks a lot for your help. I wonder if that small brass tube that stands proud on my float camber has to be a tight fit in the upper float cover, mine has a tiny crack…

[Henning G]

Just discovered that my pilot jet is too high, so the float chamber cover "rides" on the pilot jet .