No spark after doing head gasket 98 3.0

[lr3guyjoe]

Just got done doing the head gasket on a 98 3.0 and now after getting it all back together I have no spark. The only thing I disconnected electrically was the choke, temp sensor, neutral lockout and removed the coil pack. Everything is wired back up.

Before I did the head gasket it had great spark.

I checked out all the voltages and grounds all checked out fine. I checked out the coil and it ohmed out fine per a diagram I found on here. The result of it said replace the ignition control module. So I did that. Still no spark. I changed the rotor and cap. No spark.

So I did some more digging and I found the Mercruiser 3.0 service manual "Number 26"

I started the troubleshooting section for spark and didn't get all that far. I got to Step 1A where it says pull the 4 terminal plug on the distributor and low and behold spark!

Now I'm stuck.. what is the magnetic shaft assembly? I wrongly thought it was the magnetic pick-up coil and replaced that.

Is it the actual distributor shaft?

Seems suspect that I'd loose spark right after fiddling with the head.

 

[alldodge]

Look at page 4B-6 of your manual letter (a)

Look at page 4B-13 to test

 

[lr3guyjoe]

Hey thanks for your reply.

I did the test on the coil as described and it checked out I got 800ohms and no shorts to ground. I did get a replacement when I got the other parts and it tested the same and I put that in just incase.

The magnetic plate that you referenced (a) doesn’t look replaceable.

I guess I’ll look for a distributor assembly.

So when I unplug the 4 prong plug and it sparks the plugs look like they are all firing correctly. Why would it spark with that unplugged? Is it strictly firing from the coils to the distributor with no spark curve control?

 

[alldodge]

To me letter (a) is the distributor coil item 6
https://www.mercruiserparts.com/bam/subassembly/30920/2330/50

Its firing from the distributor coil, just needs 12V supply. The spark will not be as high as what comes from the main coil but should cause a timing light to flash

Make sure you have power on one side of the shift interrupter and also on the White/Green wire going into the 3 prong plug

 

[wrench 3]

That trouble shooting chart completely ignores the shift interrupter switch. Considering the circumstances my money would be on that switch. Could you have messed up the shift cable adjustments or grounded a wire there?

 

[lr3guyjoe]

I’ve got the shift interrupter bypassed

 

[wrench 3]

If by "bypassed" you mean that the leads are connected together that won't work. It's a normally open switch and you need to remove the wire coming from the distributor and isolate it from any ground. If that fixes the problem, you have a bad switch or it's out of adjustment.