First post, hoping someone can help....
I have a type 127 1800 type 4 motor, with PDSIT 36/40 carbs - believe this as pretty much a euro spec 411/412 motor...
Just given it a service, valves all set .006", double checked.
It's timed 7.5deg BTDC at idle, 28/30 at 3500 with hoses off, double checked. Single vac-can bosch distributor, can't see model number now fitted.
I have a mild popping/backfire when releasing the throttle quickly, on the overrun.
Have checked for vac leaks, manifolds and carbs torqued correctly, exhaust seens fine.
Was previously set up by someone else with timing well out from above (32deg total advance, hoses connected) and carb adjusted to suit. I wonder if idle mixture is now a little lean and that's causing my issue?
Which is the idle mixture screw on the 36/40 - is it the plastic thumbwheel at the carb base or the inset brass screw half way up the carb body please?
Hoping someone can help as the motor is in my bus and I'm supposed to be taking the family away for 2 wks in 2 days time!
Thanks very much....
Flip