Mercruiser 5.0 thunderbolt 5 no spark

[EJF3]

I have a 98 sea ray 215 express cruiser. Mercruiser 5.0 with thunderbolt 5 ignition alpha 1 gen 2. Serial number for engine 0L019753. My boat died on me in the middle of the lake and won't start. There's no spark. This is a fresh rebuild with less than 5 hours on it. I jave pulled the grey wire from distributor to the tack. No spark. 12.3r volts at both batteries. Has new cap rotor wires and plugs. Replaced ignition sensor in the distributor. Only getting 10.5 volts out of coil and the ignition module. Replaced the coil. Still no spark and same 10.5 volts. Before I spend over 600 on a new module. I just want to be positive about the module being the issue. The trouble shooting chart says if its 0 volts its bad. I still have 10.5 also would the module just break down while driving?

 

[Scott Danforth]

follow the troubleshooting tree (in the stickies)

most likely its the $45 trigger assembly in the distributor. the upgraded ones have 3 wires (extra ground)

 

[dubs283]

op says replaced ignition sensor? personally i would only use the quicksilver brand, have found aftermarket ones to be not reliable

to op:

im guessing you verified spark by striking the wht/grn wire to ground, yes? this tells you coil and module are okay

try jumping 12 volts directly to coil (+), get spark now? 10.5 volts at coil is low

 

[AShipShow]

also, try checking the coil voltage with the negative lead of your meter directly to the battery.. if its full battery voltage you have a bad ground connection to the motor. If its still low, then you have a bad positive connection somewhere or a high resistance short somewhere.

If you conclude that you're module is bad, you might look at switching to the Delco EST ignition system... Same thing happened to me a month or two ago and I made the switch. Very happy with it.

 

[EJF3]

op says replaced ignition sensor? personally i would only use the quicksilver brand, have found aftermarket ones to be not reliable

to op:

im guessing you verified spark by striking the wht/grn wire to ground, yes? this tells you coil and module are okay

try jumping 12 volts directly to coil (+), get spark now? 10.5 volts at coil is low

Both the old and new coil has the same voltage. I tried striking the wht/green to a ground and still no spark

 

[EJF3]

also, try checking the coil voltage with the negative lead of your meter directly to the battery.. if its full battery voltage you have a bad ground connection to the motor. If its still low, then you have a bad positive connection somewhere or a high resistance short somewhere.

If you conclude that you're module is bad, you might look at switching to the Delco EST ignition system... Same thing happened to me a month or two ago and I made the switch. Very happy with it.

With the volt meter using the negative on the battery only getting the 9.5 at coil and out of the LCM.

How difficult is it to install that delco est ignition system?

 

[EJF3]

op says replaced ignition sensor? personally i would only use the quicksilver brand, have found aftermarket ones to be not reliable

to op:

im guessing you verified spark by striking the wht/grn wire to ground, yes? this tells you coil and module are okay

try jumping 12 volts directly to coil (+), get spark now? 10.5 volts at coil is low

I tried jumping the 12 volts directly to the coil and still no spark

 

[EJF3]

The module is getting warm just turning over the motor. Should it be heating up? Also with jumping the coil directly to the battery im getting 11 volts out of the module

 

[dubs283]

I tried striking the wht/green to a ground and still no spark

seeing as how you replaced the coil and coils rarely ever fail most likely it is the ignition module, not uncommon for them to get warm but just cranking it shouldn't be overworking it much

there is a way to test the module that merc does not outline in the manual, voltmeter on dc volts red lead attached to module wht/red output lead, black lead to good clean ground, verify voltage with key on. hold wht/grn wire to ground and watch for a momentary drop in voltage from the wht/red lead then return to battery voltage. if there is a momentary drop the module is good, no drop module is bad