Can you Help with my Furnace Problem

[dnrtheil]

Long story short.
Used Furnace NT30 with spark ignition.
After install, the furnace ran through two complete cycles, fan start, heat up, cool down, fan off. On the third try it would not produce a flame. I am 100% sure the sail switch works, the ignitor produces a spark, I can smell gas outside at the exhaust port, I can also hear gas leave the LP tanks while the furnace is trying to start. Is there a chance the spark is not enough or that I am not getting enough gas into the combustion chamber to produce a flame? I see a couple of on-line stores do not let you return a gas valve and at $90.00 I am hesitant to get one and that not be the problem.
Any thoughts?

Thanks - Derek