Need some direction here.
C&S BT 900 dual needle/seats Alky Carb on E85 stalling when put in gear.
Raising or lowering idle speed doesn't correct it.Idles fine.
Float levels correct,idle speeed adj. with rear butterflys/allen ,Ft.butterfly factory setting,adj. idle air screws minor.
Carb. just received back from C&S with a good bill of health.
Boat- BBC 509 c.i.,TT S475's,2 Intercoolers, 60 mm wastegates set for 20 psi.,50 mm B.OV.,MSD locked @35 deg w/boost retard set pulling 3 deg. right now.
When put into gear it will stumble and catch itself sometimes but generally if i can't pump throttle in time it stalls.Acceleration from idle to cruise fine with no stumble or hesitation .
No fun around the docks or other Boats.
Any suggestion appreciated.

 

Timing looks okay , what does your wideband say at idle ? Might be a little lean when you pull it in to gear.

 

Thank you for your reply. I think my wideband is out to lunch. The parameters that came with it are 9.8-1 cruise & 8.1 w.o.t..
I have jetted up and down with both primary &sec. jets with a constant 9.8-1 to 9.5 reading. I just turned it on with engine not running for 2 days stone cold and get a 9.7-1 reading. FAST ethanol single sensor unit.I am currently back at fact. jetting with decent plug reads.

I am not currently running a thermostat,so i think i'll throw one in to see if that helps my stalling also.If not will minor adj. the ft. butterfly help ?
This is an all new installation also.

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How did you adjust the idle mixture screws? I would not change the front throttle blade adjustment because that adjustment helps it throttle away from idle so clean.

 

I just adjusted them slightly by ear after each change in idle speed with rear/allen . I'll have to order a new sensor to see if it corrects my calibration.
Thanks for the info Tim !