4.3L Won't start!

[ckneifl]

i have a 2002 caravelle, with a 4.3L mercruiser, last week i dumped a can of seafoam in it and ran it all day it ran fine, this week i put it in water and had a hard time starting, it started an i ran it up and down river for awhile, shut it off and now will not even show any signs of starting, i have a spark tester, spark from the coil is very good but to plugs it looks weak, i swaped out a coil and module from another boat, still not firing, can it be that little ignition box in the distrubutor or does anyone hav any other suggestions, i removed line going to carb and it pumps fuel fine out of that,i also tried dumping a little gas down carb and nothing, i also replaced all the spark plugs.

 

[guyjg]

...spark from the coil is very good but to plugs it looks weak,

Then it may just be the dist. cap and/or rotor or wires, but not likely the wires.

...can it be that little ignition box in the distrubutor...

You eliminated the spark trigger because you get good spark from the coil.