#3 Plug not firing for 1st 10 minutes

[roger3645]

Running a 1991 Johnson 70hp on a 16? aluminum bass boat. I only have this problem after initial start up. When I first start the motor and head for my first spot, the number 3 spark plug will not fire. After about 10 minutes the plug will start firing and it will run good the remainder of the day. I?m certain it is the plug not firing. I started it up in the driveway and put a timing light on each spark plug no spark on #3. After running the motor for a while #3 plug began to fire. I have changed the spark plug and coil. Still the same only it does not take as long for the plug to start firing.

Soooo Why it do dat?????

Thanks Roger

 

[CharlieB]

Re: #3 Plug not firing for 1st 10 minutes

Very interesting problem.

Usually as an ignition system warms components FAIL, yours is just the opposite!

First thing is to make sure that all connections are clean and tight.

Ignition module connectors to the stator, triggers, and wires to the coils.


If this doesn't cure the problem then you need to test the triggers and stator individually following the steps lined out in the (FREE) CDI Outboard Ignition Troubleshooting Guide found by a link at their site CDI.com

There is no bench test for the ignition module, it is a process of elimination, if all else checks out then the module may be your culprit.

Test, test and test again to make sure before even thinking about ordering any NON-returnable electrical part.

 

[ezeke]

Re: #3 Plug not firing for 1st 10 minutes

Very interesting problem.

Usually as an ignition system warms components FAIL, yours is just the opposite!

First thing is to make sure that all connections are clean and tight.

Ignition module connectors to the stator, triggers, and wires to the coils.


If this doesn't cure the problem then you need to test the triggers and stator individually following the steps lined out in the (FREE) CDI Outboard Ignition Troubleshooting Guide found by a link at their site CDI.com

There is no bench test for the ignition module, it is a process of elimination, if all else checks out then the module may be your culprit.

Test, test and test again to make sure before even thinking about ordering any NON-returnable electrical part.

http://cdielectronics.com/ will work better.

 

[MNSouthwestfishing]

Re: #3 Plug not firing for 1st 10 minutes

Very interesting problem.

Usually as an ignition system warms components FAIL, yours is just the opposite!

First thing is to make sure that all connections are clean and tight.

Ignition module connectors to the stator, triggers, and wires to the coils.


If this doesn't cure the problem then you need to test the triggers and stator individually following the steps lined out in the (FREE) CDI Outboard Ignition Troubleshooting Guide found by a link at their site CDI.com

There is no bench test for the ignition module, it is a process of elimination, if all else checks out then the module may be your culprit.

Test, test and test again to make sure before even thinking about ordering any NON-returnable electrical part.

One way to test some of the components is to switch them around on your motor. (i.e. instead of replacing the spark plug try it in another cylinder to see if the problem stays in the same cylinder or moves with the part you move) I know this is a simple concept and seems obvious although I have spent a lot of money chasing simple fixes You said you replaced the plug and coil what about the plug wire? Also does ambient air temperature have anything to do with how long it misses for?

 

[roger3645]

Re: #3 Plug not firing for 1st 10 minutes

Thanks guys I'll check the connections tomorrow, out shopping with the wife today. I'm sure one of you guys saw me. I was the guy holding his wife's purse.

Yes I did change the coil wire as well. The first time I took her out after changing the coil and plug #3 fired right away. Second time out is when she started not to fire again. Don't suspect air temp matters one way or the other.

 

[kenmyfam]

Re: #3 Plug not firing for 1st 10 minutes

I was the guy holding his wife's purse

So that was you was it ????

 

[bktheking]

Re: #3 Plug not firing for 1st 10 minutes

Move the powerpack wires around on the muffs when it's not firing and see if something changes, I had a motor that would do this, it had a shorted wire going into the power pack, replaced and it fixed it.

 

[roger3645]

Re: #3 Plug not firing for 1st 10 minutes

Yes the powerpack wires, I'll check them as well. Had a bad wire in my last powerpack, took me forever to find that.

 

[Texasmark]

Re: #3 Plug not firing for 1st 10 minutes

I have an '02 3 cyl 90 Merc that did the same thing. I fooled around with it trying to catch the culprit. My engine has 3 separate packs; one per cylinder.

One day, while it was cold, I put it on the muffs and stuck a piece of wire under the plug rubber boot on the plug wires.

I cranked her up and with a screwdriver, arc jumped the ignition (via these wires) to the block. 2 put out a nice blue spark, the other didn't spark at all.

I let her run and got the block at thermostat release temp and performed the test again. 3 put out a nice blue spark this time.

$100 and and a pulse pack installation later, my problem was gone.

Worth a try and the test costs next to nothing.

Mark

 

[roger3645]

Re: #3 Plug not firing for 1st 10 minutes

Well went over the connections and everything seemed ok. Hooked the timing light to #3 started it up and nothing from #3. While holding the the trigger down on the timing light I touched the wires from the power pack and boom there went #3 firing like it is suppose too.
I tried giggling the wires to see if #3 would stop firing but I couldn't make it miss.

2nd powerpack that's had wiring problems.

I'll try it again just to make sure.

Thanks Guys

 

[bktheking]

Re: #3 Plug not firing for 1st 10 minutes

Pull the power pack plugs and look for corrosion or a misaligned connector and check the ground while you are at it.

 

[roger3645]

Re: #3 Plug not firing for 1st 10 minutes

Will do thanks

 

[CharlieB]

Re: #3 Plug not firing for 1st 10 minutes

If you have a single ignition module then more likely it is the trigger wire than the stator, a stator would affect all cyl's.

Sometimes we get lucky and find a trigger wire broken at a flew point that we can get to and repair without much difficulty, saving the cost of an $$$$ trigger assy.

Disconnect the #3 trigger from the module and attach an Ohms meter, support the trigger wires near where they come out from under the flywheel with one hand, watch the meter while you gently tug on the terminal of #3 wire. If the meter shows a lose of contact then the wire is broken inside the insulation sheath. Continue to gently pull, watch very carefully to see if the insulation begins to stretch at the break or for the wire to pull out of the sheath. Repair as needed.