Logo
FULL SITE MENU

2005 Mercruiser 30 NO Spark

T

tlo1733

New member
"Need help, Boat ran great all

"Need help, Boat ran great all summer, took down to lake last week, and would not start, from what I can tell I have no spark at the coil or plugs, It has the EST Ignition system. From what I have read I am supposed to have 12v at the purple wire on the coil when ignition is turned to run, and I do not. I have checked the switch and I have power at the purple wire when I turn switch to run, I also have power going through the kill switch when switch is turned to run. I am thinking coil went bad, but the local Marine shop that is very unlikely with EST Ignition. Any thoughts would be appreciated.
Thanks in advance."
 
It is possible that you have b

It is possible that you have bad or improperly adjusted shift interrupt switch. Jump the two wires on this switch and then check for spark.
 
"OK I jumped the 2 wires on th

"OK I jumped the 2 wires on the shift interrupt switch, still nothing, I also checked the lead from the coil to the distributor #19 in the diagram, I have current through both wires. My main question is shouldn't I have power to the purple wire on the coil and shift interrupt switch,and tach. I have power to the purple wire on tach only. I have also searched for a inline fuse, nothing. Any more sugestions would sure be appreciated."
 
"I also have a 2005 3.0, I wil

"I also have a 2005 3.0, I will check the purple wire at the coil with the ignition in the run postion for power and will report back shortly..."
 
Update....I have +12 volts

Update....I have +12 volts on the purple wire at the coil and the shift interrupt switch when the ignition is in the run position. Have you checked the ignition switch?
 
"Shorting the two wires on the

"Shorting the two wires on the shift interrupt switch will kill the ignition. Do you mean to jump the neutral safety switch? With the shifter in neutral, just put the voltmeter on the slave solenoid small yellow w/red stripe wire and turn the ignition to start. If it shows 12 vdc the switch is working. W/the key in the start position there should be 12 vdc on the two top terminals and the starter should be cranking."
 
"I have 12 volts at the slave

"I have 12 volts at the slave solenoid small yellow w/red stripe wire while cranking. Does anyone have a wiring diagram, This purple wire I know goes from the switch to the tach, to the coil and then to the shift interrupt switch. Does anyone know if it goes anywhere else, or through any relays, junctions etc. And thank you very much so far."
 
"<center><table border=1><tr><

"<center><table border=1><tr><td>http://www.marineengine.com/discus/icons/mime_pdf.gif""" align=left alt=""application/pdf"">3.0L wiring Diagram
[url=""][b]Merc 4cyl wiring service bullit.pdf[/b][/url] (60.2 k)</td></tr></table></center>

Tim, reading all your posts, it seems to me you do not have 12v on the purple wire, anywhere on the engine. Please confirm.

"I am supposed to have 12v at the purple wire on the coil when ignition is turned to run, and I do not." Your purple wire is broken somewhere between front instrument harness and engine harness. try wiggleing the connecting plug on engine(mounted on starboard exhaust elbow). also, if no power on purple wire at engine, no need to suspect coil is faulty.
"My main question is shouldn't I have power to the purple wire on the coil and shift interrupt switch,and tach." YES, and that is your problem. keep looking for break in purple between front and rear of boat, try jumping a long wire from Purple at Ig switch to purple on engine harness. see if you get spark then.

Purple wire on engine goes to;
1/ Shift Interupt switch
2/ Coil
3/ Alternator
4/ electric Choke (2 barrel mod only).

All of the above should have 12 volts on em with ignition turned on. If there isnt, I suspect the big plug where font harness plugs into engine harness. There should be 12v on purple pin 5. Difficult to test as when you un plug it, you loose power feed from engine to front Ignition switch. [img]

BTW, the shift interupt switch, on your engine, connects to the ignition +12v purple wire, and switches to the white/grn to the distributor. I dont know if it is normally open or closed. Maybe some one else can confirm. Irrelevant neway, your issue is a dead purple wire....
On older (traditional) engines, Switch does not connect to +12v Purple wire such as yours, it connects to tigger wire on dissy, grounds it, to kill ignition (normally open). Mark."
 
"<center><table border=1><tr><

"<center><table border=1><tr><td>http://www.marineengine.com/discus/icons/mime_pdf.gif""" align=left alt=""application/pdf"">Merc 3.0L front Instrument wiring diagram
[url=""][b]Merc front Inst wiring diagram.pdf[/b][/url] (48.4 k)</td></tr></table></center>

Tim...dumb question time.
Do you have a switch on your front controller (little red one), thats kills your ignition? If so, it works by breaking the purple wire.
Is it off? Mark."
 
"Fantastic News, the diagrams

"Fantastic News, the diagrams worked, It was were the front harness plugs into engine harness.
It looked fine, but I lossened the clamp and wiggled it together and tried it and I have power to everything. I really do not understand what happened as there is no corrosion, the clamp was tight, looks are deceiving. Anyway thanks everyone for the help."
 
Tim

That main wire harness

Tim

That main wire harness connector typically does not come with a hose clamp on it. I have always reccommended puting one on and tightening it up to keep the two halfs together.

Of course do not over tighten but a very snug fit is good.
 
Back
Top