Bad coil? 350 mag mpi

[jetpartner]

Engine misfire, backfire and died. Changed coil, cap rotor, and sensor engine ran great. Five hours later same thing, changed coil again engine runs great. Any ideas? bad coil, bad voltage? I had a mercruiser mechanic come out and scan for codes, nothing noted, checked fuel pressure 32 psi erratic, said pump was bad. I changed filter, pump and regulator, this was not the problem. Changed coil engine fired right up. Next time someone tells you that the fuel pump is bad, asked them to change it, I think SEA RAY built the boat around the pump, what a pain to change!!

 

[jag3man]

Just wrote you a nice long email and then spell check erased it. Did you change out the amplifier at the base of the distributor? It's the small black plastic pack the provides power to the coil. Mine failed and it cut out like you said. Mine never came back but you could have an amp that is breaking down under high temp and then healing while you do all the others things you spoke of. I'd make sure that got switched and then try her again. The last part of the HT chain is the little pick-up at the very bottom of distributor and that could crap out as well. It is the widget that has replaced the old points we used to have to mess with. I'll post this without then spell check.... Please note that changing the pickup coil in the distributor is NOT for the faint of heart. You have to physicall remove and dismantle it. Very scary.

 

[jetpartner]

There is no ignition amplifier on the MAG MPI just coil, sensor and ecm. Thanks for the input.