3.0 starts but dies

[lovetheyz]

88 mercrusier i think. anyhow what is the correct wiring to the coil. i have the purple/yellow wire and a yellow wire with a piece of purple tape on it. I would assume that the original wire was replaced and that was the way of tagging it. i know the purple/yellow wire goes to the starter. am i correct that the other wire goes to the alternator if so where on the alternator?

the big issue i am having is it will crank and start but as soon as i let of the key it dies. what is causing me to lose fire after i let off the key? Its like its loosing its constant power not sure

thanks for any help

 

[Bondo]

Re: 3.0 starts but dies

88 mercrusier i think. anyhow what is the correct wiring to the coil. i have the purple/yellow wire and a yellow wire with a piece of purple tape on it. I would assume that the original wire was replaced and that was the way of tagging it. i know the purple/yellow wire goes to the starter. am i correct that the other wire goes to the alternator if so where on the alternator?

the big issue i am having is it will crank and start but as soon as i let of the key it dies. what is causing me to lose fire after i let off the key? Its like its loosing its constant power not sure

thanks for any help

Ayuh,... That wire should be the keyed Ignition circuit,.... It should be 12v, whenever the key is "On",....

 

[thumpar]

Re: 3.0 starts but dies

Do you have voltage at the coil when the key is on? It sounds like a resistance wire setup. When you are cranking the coil gets full voltage. Once you let off the voltage comes from the resistor wire and should be 7+ volts.

 

[lovetheyz]

Re: 3.0 starts but dies

So the wire that is not original(my yellow wire with purple tape) should have constant power with the key on? and it should be a resistor wire? if that is the case then the wire that was spliced needs to be replaced with a factory resistor wire or some type of in line resistor with new wiring?

thanks for any help

 

[thumpar]

Re: 3.0 starts but dies

What is your engine serial number?

 

[Fun Times]

Re: 3.0 starts but dies

Hi there, I figured maybe you might like to see some additional information as we had a really good conversation of how this system works. Maybe you'll find it to be helpful.

http://forums.iboats.com/mercruiser...ctronic-ignition-voltage-question-623195.html

Good luck.

 

[lovetheyz]

Re: 3.0 starts but dies

my serial number is 25561. i tested my voltage i am only getting 12-13v to coil when starting. once the key is released from I loose all voltage to coil.

I have replaced the points and have good healthy spark at start. tested coil and its good.

thanks

 

[GaJeff]

Re: 3.0 starts but dies

You got to have 12v switched power, if it needs a resistor or not otherwise it's like turning the key off. You should be able to turn the key on and have 12v to the coil. Then when you turn the key to crank the ignition wire supplies voltage to the starter solenoid. When you turn the key off it takes the 12v away from the coil killing the spark.

Find your 12v switched power at the key switch. That color wire should have 12v at the coil when the key is on. if not you may have a break in the wire somewhere in the harness.

Jeff

 

[thumpar]

Re: 3.0 starts but dies

You got to have 12v switched power, if it needs a resistor or not otherwise it's like turning the key off. You should be able to turn the key on and have 12v to the coil. Then when you turn the key to crank the ignition wire supplies voltage to the starter solenoid. When you turn the key off it takes the 12v away from the coil killing the spark.

Find your 12v switched power at the key switch. That color wire should have 12v at the coil when the key is on. if not you may have a break in the wire somewhere in the harness.

Jeff

On a points system the coil only sees 7-9 volts not a full 12v. It will blow though points and can overheat the coil if it is a full 12v when "on". The only time it should see 12v is when cranking.

The serial number posted is not a mercruiser serial. Look on the side of the valve cover or a tag down by the starter on the starboard side. They usually start with a 0 followed by a letter unless it is a lot older.

 

[GaJeff]

Re: 3.0 starts but dies

On a points system the coil only sees 7-9 volts not a full 12v. It will blow though. oints and can overheat the coil if it is a full 12v when "on". The only time it should see 12v is when cranking.

The serial number posted is not a mercruiser serial. Look on the side of the valve cover or a tag down by the starter on the starboard side. They usually start with a 0 followed by a letter unless it is a lot older.

Your absolutely right... i guess what i was trying to point out is that you need that switched power to run. When i got my bboat it was wired without a ballast resistor and with the key on engine off it got really hot and burned the switched power and damaged the coil. The PO told me he had just done maintenance on the ignition system... i guess he left it out. I rewired it and never had another problem.

Anyways, thanks for pointing that out... it would be considered bad advice on my part if not