Mercruiser 260 no spark

[CaliFormula]

Hi there, I’m at my wits end.
Serial number: 6765655

I have run through the flowchart numerous times.

I have replaced the coil twice, cap and rotor twice I just replaced the ignition sensor in the distributor.

With the key on I have 12v on both + and - terminals (not sure if that’s a problem)

i have disconnected the grey tach lead as well as the shift interrupt (Alpha 1)

I have have oil pressure when it cranks.

I have cleaned all of the battery and ground connections.

i replaces the solenoid because someone said to (getting desperate)

please help!

 

[wellcraft-classic210]

1 idea -- Make sure your shift cutout switch is not stuck on -- you can disconnect it temporarily for the test but be advised it wont want to come out of gear when on the water. Also look at your other grounds fo a good connection.

 

[CaliFormula]

I’ve already disconnected the switch (white/Green at the switch to rule that out and cleaned every ground.
Thank you.

 

[Bt Doctur]

Thunderbolt IV or V

 

[CaliFormula]

Thunderbolt IV, sorry.

 

[Bt Doctur]

http://www.boatfix.com/merc/Bullet/83/83_24.pdf

 

[Bt Doctur]

http://www.boatfix.com/merc/Servmanl/18/18B4R2.PDF

 

[achris]

http://forums.iboats.com/forum/engi...-mercruiser-thunderbolt-ignition-systems-work

 

[CaliFormula]

Update, I went through and cleaned all the contacts again and now when I turn the key to the on position I blow the ign fuse? I must have a short somewhere right?

 

[achris]

Update, I went through and cleaned all the contacts again and now when I turn the key to the on position I blow the ign fuse? I must have a short somewhere right?

Yeah, blowing a fuse is usually an indicator of a short.

Chris......

 

[CaliFormula]

Ok fixed the short, totally my fault. When putting leads back I created a short myself in the fuse panel.

I’m still not getting spark to the plugs.

From the flow chart

Removed white/green from shift switch (Alpha 1)

removed tach gray lead from coil -

cleaned all terminals and tight clamp on distributor

power at + on coil (11.7)

power at red/white terminal at distributor (10.6)

spark gap tester on high high tension line to ground and I get spark. (Replaced ign sensor in distributor again)

I’m at a loss.

I will post a pic of my breaker and 90 amp fuse.

 

[CaliFormula]

Update question

while grasping at straws and changing my cap again I noticed that the whole the rotor is pointing at cylinder 1 the tooth on the rotor is not lined up wit the sensor in the distributor. Does this mean I’m off a tooth? Am I parking in between the connections on the cap and that’s why I’m not getting spark to the plugs?

 

[CaliFormula]

Well that wasn’t it. I moved a tooth in either direction and it made no difference.

I now notice a different issue. When I turn the key to the on position I have voltage on my gauge but when I turn the key farther to start the boat the voltage drops down and pins to O. Bad ignition switch or am I grounding out somewhere in the starter path?

 

[CaliFormula]

The breaker is not popped and I checked for continuity through it.

 

[Bondo]

I now notice a different issue. When I turn the key to the on position I have voltage on my gauge but when I turn the key farther to start the boat the voltage drops down and pins to O. Bad ignition switch or am I grounding out somewhere in the starter path?

Ayuh,..... Have you cleaned to shiny metal Clean the battery terminals,..?? both (+), 'n (-),..??

How about the other ends of both battery cables,..??

 

[achris]

...spark gap tester on high high tension line to ground and I get spark. ...

Almost missed this little gem.

So, you ARE getting spark from the coil, just not getting to the spark plugs.... Your ignition module and sensor (inside the distributor) are working perfectly, so you can stop messing with them. The problem is either the HT leads, the cap or the rotor. Can't be anything else...

Chris........

 

[CaliFormula]

Ayuh,..... Have you cleaned to shiny metal Clean the battery terminals,..?? both (+), 'n (-),..??

How about the other ends of both battery cables,..??

I’ve cleaned every contact with wire brush and then fine sandpaper.
I followed the cables from both batteries and cleaned every connections.
Thank you.

 

[CaliFormula]

Almost missed this little gem.

So, you ARE getting spark from the coil, just not getting to the spark plugs.... Your ignition module and sensor (inside the distributor) are working perfectly, so you can stop messing with them. The problem is either the HT leads, the cap or the rotor. Can't be anything else...

Chris........

I’ve tried new caps and rotors, I’ll pick up some new HT leads tomorrow and give it a shot.
Thank you

 

[CaliFormula]

Update so it turns out I am getting spark at the plugs plugs. I pulled a plug out and cranked and had a good spark. Not sure why the timing light doesn’t register it.
So now u have spark, fuel, compression. Why am I not starting?

 

[achris]

Spark at the right time?