99 3.0 mercruiser no spark at spark plugs

[Desertson1410]

I need help i have no spark on my 99 bayliner with a 3.0 mercruiser. So let me start on how this all started. I was changing my oil pressure sender and grounded it out with the starter slave solenoid dumb move I forgot to disconnect the battery. So i lost all power the 50 amp fuse blew out so replaced it. after that the starter slave solenoid would click but starter would'nt turn over so I fried the starter solenoid, replaced the starter,boat turns over but wont start so i changed the ignition coil with no success. took all the spark plugs off cleaned them to see if there was a change maybe some fuel or black build up... nothing. i have tested the slave solenoid voltage, performed the test checked the ignition switch it was good i have 12.3 volts at the starter and at the slave solenoid i even tried disconnecting the grey wire to the tach because i read that it might ground out. I cant seem to figure this out can some one please point me in a good direction

 

[Maclin]

How are you sure it has no spark?

If yours equipped with the kill switch? Under the Throttle control? If so make sure it is in the Run position.

Even if you are sure it is a no spark condition make sure you have fuel in the carb. Look down the throat and see if 2 good streams of fuel squirt in when the throttle is moved.

 

[Desertson1410]

Kill switch is in the on position and there is fuel in the carb and 2 streams of fuel in carb

 

[Desertson1410]

I'm sure because I removed a spark plug connected it to the coil directly used the plug from the coil grounded out the spark plug turned ignition to the on position which should have gave me a spark

 

[Maclin]

Not the best way to gauge spark. The way you tried it the distributor would need to be turning in order to trigger a spark. You need to crank the engine while looking at a spark plug. A spark tester would be best. A free test is to remove a sparkplug wire from a plug, stick a phillips head screwdriver in it and place close to a ground then crank for a short time, should see a bright blue spark.

 

[jimbo_jwc]

Test with ignition switch on and open points with small screwdriver to see if you see a spark across the points or on plugs . This is your running circuit with reduced voltage from resistive wire . The starting voltage is full voltage from your solenoid on top of your starter to make hotter spark then from when its switched to the feed from your dash . The contactor that starts your starter has a separate contact in it to begin with and is off when you let go to run .

 

[achris]

Test with ignition switch on and open points ... .

Where exactly does he find the points on an EST ignition system? (Read the thread title, 1999 engine)

Chris....

 

[Desertson1410]

Thank you. I will try these 2 methods as soon as I get home. Greatly appreciate your time and help.

 

[Desertson1410]

Ok so I bought a spark plug tester. Connected the tester to the coil plug and the other end to a spark plug in the engine. I turned the ignition and the spark plug tester did not light up. So does that mean that my neutral start switch is bad due to all the voltage is present but won't send power to the coil??

 

[Maclin]

You need to crank the engine over for this test.

 

[Desertson1410]

I finally got spark plugs to light up and the engine will spit up gas from the carb could it be that the rotor and cap are bad since it's not sending voltage to the spark plugs?

 

[Desertson1410]

Just wanted to update the thread. So I finally got my boat running and I basically replaced the whole ignition system but in the end it was the harness from the coil pack to the distributed. The red riwre has an in line resister that had blown so no power was gettinting to the distributor. Need to get the ti.ing right and it's boating time. Thank you to everyone who took the time to help.