with 18 raker it should fly from zero. 18 is small for that motor . maybe need 12 to 13 mm vent holes, omc vents are too small.

have you tried with plugs and no copper washer ? it will let the spark be in the correct place to fire.

I also asked lots of people about the tuner to make it shorter, but everyone who is expert on tuners say you will lose bottom end power on v hull.
short tuner just for very light tunnel hulls. ?