I have a 1996 Glastron GS 205 40th anniversary edition with a 5.7 litter mercruiser thunder bolt ignition. I just rplaced the ignition module, cap, rotor, plugs and wires. it ran fine all day. towards the in of the day it started sputtering and then died. could not get it started again. After it sat for a day, i tried to start again and it tried to fire but just couldn't. what should i start with first? Fuel/water filter? fuel pump? oil pressure switch?
First check the water separating fuel filter. Make sure it's not full of water. Do not re use the filter. Pouring it out contaminates the clean side. Put on a new filter and fill it with fuel first if you can. (makes it easier on the fuel pump if you do)
What is the serial number off the motor? Is it an efi motor or does it have a carburetor?
So I installed a new fuel/water filter and It still won't start. It wants to fire but won't. Before it died in the water, it stuttered and died and wouldn't start again. Should I check the oil pressure safety switch? If so, where is it? Engine serial # XXXXXXXXMercruiser 5.7 liter v8 thunderbolt V ignition
Your motor doesn't have one of those. You only have an oil pressure sender for the gauge. At least, that is what the motor with the serial number you gave me has.
You need to check your fuel pressure to make sure you are getting fuel to the carb. I think your fuel pump may have failed on you. If you have any starter spray you can give the motor a shot of it and see if that makes it fire briefly. Check to make sure the choke is opening all the way as well.