I know many people will have asked this in the past but i need some advice. I went to buy some fuel at the LHS. My kids were getting wild in the store so i was being as quick as i could to get out the store. As i was in a hurry i picked up the wrong fuel i got 4 stroke instead of 2 stroke. it has 15% nitro which i always use but only 16% lube. OS recomened 18% lube to avoid damage to the engine. my question is can i just go ahead and add castor to the fuel to make up the 2 % the jug i bought is 1 gallon how much extra castor should i put in? the engine i have is an OS 46 MAX FXI thanks paul