I have a 1982 yamaha It175 that i’ve never seen run. I recently replaced the top end on it. It has spark, compression, fuel, and air. I cant think of anything else to check on it. I’ve sprayed gas directly into the cylinder and it shows no signs of life. However; sometimes when I’m trying to kick it over it will ignite for a split second. I’ve taken the reed valve out and checked it, it’s not in the best of shape but that shouldn’t cause the engine to start up at all, should it? I’m stuck. anything and everything will help if anyone has suggestions.