Here is the owers manual from the 1.10. Same layout as the 91. http://yspartsandservice.com/pdf/FZ110.pdf

You only need one check valve. Also, make sure you use a quality name brand fuel tank. I've used Sullivan, Hayes and Dubro w/o problem, but I split a tank supplied with an ARF once. I won't let THAT happen again.

Just for clarification, looking at the engine from the front, the left nipple goes to the clunk, the right nipple goes to the check valve and the vent. The check valve should "blow" Toward the tank. You will need TWO 1/8" "T's" and two fuel Dots. Like this.. http://www.horizonhobby.com/Products...?ProdID=HAN115

One T must be between the check valve and the tank vent. The second one anywhere between the tank and engine.