1989 Sea Ray Sundancer 340 7.4 Thunderbolt Ignition Issues

[KnottaYachta]

Was on the lake this past weekend and at about 3/4 throttle on both 7.4 engines, the starboard engine backfired a few times and I throttled up both engines to try and clear it out and the starboard engine stalled out. While trying to restart, it would start, backfire a few times and die. I found that if I hold the key in start position, it would run with no issues, but when I turn the key back to run position, it would should down. I moved the ignition amplifier from the port engine to the starboard engine with no change. I pulled out the pickup coil in the distributor and noticed some corrosion, but I did not have a spare one to put back in and while I was hooking the wires back up to the studs, I inadvertently landed the black wire to the stud on the pickup coil to the white with green stripe and tried to start and the engine did not try to start at all. I moved the black wire back to the white with red wire but the engine still will not attempt to start even with the key in the start position. I am fairly certain if the pickup coil was not bad, it is now. I have a replacement on the way but I am concerned this will not resolve my issue. Any help would be greatly appreciated.

 

[alldodge]

found that if I hold the key in start position, it would run with no issues, but when I turn the key back to run position, it would should (shut) down

Check for 12V on + side of coil with key in ON position. If 12V is not there You probably have a bad ignition switch. Test switch to verify

inadvertently landed the black wire to the stud on the pickup coil to the white with green stripe and tried to start and the engine did not try to start at all.

May have burned out something but to verify run through this troubleshooting diagram. Its for a TBV but its the same as for the TB-IV

 

[KnottaYachta]

Wow, this is the first I have seen this troubleshooting guide! I am excited to give this a try after work and the replacement pickup coil should be arriving today as well. I do know that I had 12+ at the coil when key is on and 9-11 volts when starting due to starter load so that is why I am confused as to why it is dying when the key goes from start to run. I even pulled one of the spark plug wires and was watching the spark stop as soon as the key was returned to the run position. More to come after work today! Thank you alldodge

 

[KnottaYachta]

Update: the pickup coil in the distributor was the issue!!! Back on the lake!

 

[alldodge]

Thanks for updating with the answer, most don't. This is very appreciated
Happy boating