Mercruiser 5.7 engine dies

[ted4420]

I have a Bayliner with a Mercruiser 5.7 motor. It it died on the lake and would occaisionally run for less than a minute. I followed the diagnostic chart and it said I needed a coil. I installed a new Mercruiser coil. It starts easier but I have to turn the kill switch off then on and it will start again. It will run smooth for a minute and then start missing and die. If I crank the motor and turn the on/off switch on the quadrant it will start but die after 1 minute. When it starts to die I sprayed a fine mist of starting fluid and the carb. It still dies. I have put 12 volts directly to the coil and it doesen't help. I need help! Thanks, Ted

 

[jerryjerry05]

Re: Mercruiser 5.7 engine dies

Most coil operate with 9volts.The coil you replaced probably didn't have a resistor in it.It sounds like you burnt the new one.Get a coil with a resistor or install a resistor in line Chrysler used them on older cars.Make sure when you turn on the key the voltage is no more that 9...J

 

[ted4420]

Re: Mercruiser 5.7 engine dies

Thanks for your responce. The coil I took out was Mercruiser number 392-805570-1. The Mercruiser dealer sold me a QuickSilver 392-85570A. The motor starts now better than before. It runs smooth for 1-2 minutes and spudders and then dies. You can start it rite away if you shut off the ignition switch and then crank and it will restart. I have been looking at the wiring diaghram. Does the 5.7 carburated Mercruiser have a low oil/high temp shut down. I see wires going to the electronic module from the water temp. sensor, oil pressure sensor, and gear lube reservoir? Thanks, Ted

 

[jerryjerry05]

Re: Mercruiser 5.7 engine dies

That would depend on the year.Some have alarms.Measure the voltage on both sides of the coil when it running.J

 

[ted4420]

Re: Mercruiser 5.7 engine dies

Thanks,j I will do that and let you know. Ted

 

[legoman67]

Re: Mercruiser 5.7 engine dies

next if the coil did not fix i would look at the distributor, and/or fuel pump.... is its a points distributor? or electronic? if its points try cleaning the points...

also, it could be your fuel pump, is its mechanical or electric? if its mechanical check the rod that activates it. i found ours bent and that was making the engine not run for very long.