RE: Magnum 46 carb replacement
Hi Ernie:
I don't know what other OS engines the carb came on, but it did come on the following ones,
40SF, 40SF-ABC, 46SF, 46SF-ABC, 40VF-ABC, 46VF-ABC, 46SF-H, 46SF-HS, & 50FSR-H. The
Magnum carb bolts are 3X6MM and the OS is 3.5X6MM. The OS bolts will work fine on the
Magnum, actually they fit through the holes better than the Mags do which makes the carb
tighter on the O-Ring. The 32 size carb is a 7MM venturi if I am not mistaken and has a 13MM
throat. The 40-50 size has a 7.7MM venturi and a 13.5MM throat.
The carbs will work on different size engines mainly due to the fact that there isn't a lot of
difference in air (CFM) or fuel volume at WOT because the smaller engines usually turn more
RPM's then the larger ones. This is a highly simplified explanation, but pretty much covers it.
The OS4D carb has the same venturi diameter (7.7MM) and throat size (13.5MM) as the original
Magnum carb. What I like about the 4D carb, besides the fact that it is a spray bar, is the very
fine threads on both needles and the overall quality of the machine work. The 4D is a very easy
carb to adjust and the adjustments are smooooooooth!
Let me know when you try it and what you think...
Howard