5.7 Merc/B3- Ignition Coil Issue

[CatawbaRinker]

I have the mysterious "ignition coil getting hot" issue. The boat is a 1995 Rinker Fiesta Vee 265, engine is a 1994 5.7L Bravo TBI, serial # OF286058. The good news is that the boat has yet to shut down or strand me (my trips are less than 45 minutes normally), however if I run the boat for more than 10 minutes the ignition coil gets too hot and must cool back down in order for the boat to restart.

I am attaching the diagram for my engine. I am getting 12v before and after the coil. The kicker is that it looks like a previous mechanic that worked on my boat just put a Delco replacement coil in my boat when previously trying to diagnose a starting issue. I don't see anything inline that would perhaps limit and voltage. I know the discussion of auto vs marine is a can of bait but wanted to throw this issue out there before I start either tearing into stuff or ponying up for a marine coil. Any other ideas why this might be getting hot?

 

[bucklahoo]

Watching...I may be having the same issue (if not fuel related) but have been stranded. I'm in West Harbor, engine acts up and dies after trip to Kelly's and after the same amount of time on the way back. Just posted about it. Mercruiser 470. Good Luck.

 

[achris]

Check the resistance of the primary side of the coil (should be written on the coil somewhere)

If it's not the original coil, it's possibly the wrong coil.

The spec is in the service manual..

Marine coil. There's isn't a specific marine coil, you can use any coil you like, as long as it matches the spec.

Chris...