What is the correct carb for this motor ? Mine have the 4 plastic carbs. I have posted to pros on screamandfly no one seem to know the answer. The reason for my question is when I brought the engine the previous owner give me a set of "spare" carbs. I now observe the ones on my engine is 1 3/8 throat size, my "spare" is 1 5/16. My curiosity is of course which is correct ?