Small Engines (Lawn Mowers, etc.): Help Fixing a chain on a carter go cart, sprockets, sprocket

Question
Okay, here is the problem iam 14 year's old and iam trying to fix my little 8 year old brother's go cart which is sort of mine too but that is another story. My dad used to fix it whenever it would break because he was good with cars and engines. But my dad sadly died in Feb. of cancer and now i dont remember much on what he used to do to fix the go cart and the truck that my mom gave to me. So this is the problem, my brother was riding the go-cart and the chain just "fell off" as he said, and this has happended before and my dad would take some links off the chain except i forget how to take the links off. So now i have the go cart up on a jack with one of the wheels off and iam sitting her waiting for my friend Jordan to come online so i can talk to him about this ((jordan would be my 16 year old friend that loves cars about as much as my dad did)) so i would be extremely happy if u could answer this email back before Monday so i can fix it over the weekend. Thanks a whole lot. Becki

Answer
Hi Becki,

I'm sorry to hear about your dad.  You must miss him :(

The chain probably fell off for one of 2 reasons.  It was loose or the sprockets are out of alignment.  If you have adjustment on the motor mount, you can loosen the four, or so, bolts and move the engine to tighten the chain and align the sprockets.  The chain should have about 3/4" to 1" of up and down movement at the midpoint between the sprockets.  Is you were to put a straight edge (or ruler) on the side of the large sprocket, it should line up with the side of the small engine sprocket.  (You can also eyeball this from the rear of the kart.)  If you move the engine as far as it will go and the chain is still too slack, then you will need to remove a link or 2.  

Let me know how you make out.
Michael