thunderbolt IV issues

[scott_s]

boat started dropping cylinders after warming up. finally lost spark completly. replaced coil, and ran good about 3-4 hours. same issue returned. later when I checked boat, spark was ok. left it running at the dock. 1 hour later returned, engine stopped, no spark. boat brought to my shop, and when tested spark is good, fires right up. any ideas? every component checks ok. only happens when warm.

 

[04fxdwgi]

Check the control module. Electronics may be starting to weaken and breaking down under heat. Longer it runs, warmer it gets. Usually what happens in electronics if they don't flat out fail. I use a can of "Dust Off" (air in a can) and if I suspect a heat issue, I'll turn can upside down and blast the component, chilling it off pretty quick. If heat is the suspect, sometimes the component will start to work correctly again when chilled, sometimes not. Anyways, I would suspect the Thunderbolt module, going by what you describe. Also, check battery voltage B+ and ground to the module.

 

[guyjg]

It may well be the amplifier module. First check the optic trigger under the dist. rotor for rust. Old models have tiny bare wires that corrode. $50 part vs. $400 module.