Motor Problem 90hp Mercury

[Kracker Jack]

Try starting it with a little juice behind it on a boost setting on your b attery charger that should rule out weak battery. My 135 does the same thing to me with a fresh charged battery. Im thinking the starter is pooping out on me or like Ridge said it could be bad cables (corrosion inside sheathing createing resistance

[Hedge]

Have the heads have been shaved and there's too much compression?