I running some old fuel I left in a plastic can for about 6 moths with and open fuel hose. It is hard to start and the engine doesn't idle. To be fair the engine is new and I'm breaking it in so I don't know whether it is the fuel of the engine.

So what are the symtoms of wet fuel?

You have both symptoms of wet fuel but to be fair try running it in an engine that isn't new. Jim

Although that is NOT a good way to store fuel it is PROBABLY still OK. My bet is on the tuning.

If you want to check for water in fuel, put a small sample in a clean (and dry!) glass container and put a lid on it. Place the jar in the fridge to cool it and if there's any water then as it cools all the oil will suddenly come out of solution and fall to the bottom of the jar. The temperature when the oil falls out depends on how much water is in the fuel. As a guide, with zero nitro and a synthetic oil (the fuel I was testing) it'll seperate at freezing point (32F or 0C) when there's .75% water. I actually flew with 3% water added (on a warmish day) with no problems at all. YMMV

It's also possible some of the alcohol and most of the nitromethane just evaporated. Alcohol and nitro have a low vapor pressure and evaporate pretty quickly. That's why fuel feels cold on your hand even in the summer time.

Try a new gallon and keep it tightly closed from now on.

N

Water is heavier than fuel. Pour the fuel in a clear container and let it stand for a day. Check it and see if you see a line where fuel stops and water starts. Because water is heavier it will be on the bottom. I use a cup with a rod in it to check the fuel in my real Cherokee 140. I insert the rod in the hole in the bottom of the tank and this releases fuel into the clear cup. If there is water I continue to do it until there isn't any sign of it anymore.

Gibbs

I think what NCIS has described works for water in gasoline but not for water in glow fuel. Water does not separate out of glow fuel.

what you describe here is classic bad fuel but like was said , not entirely fair to test in new motor.