Ignition problem - no spark from coil

[juzza]

I got boat with a 2003 Mercruiser 3.0 (SN OM664324) two months ago and all has been ok until this week when it didn't start. Here's what I know:

1. I don't get a spark from the ignition coil
2. I have bypassed the shift cutout switch
3. I get 11.5V to the ignition coil
4. I get 11.5V (on both wires) to the distributor cap
5. There is no continuity from the coil tower (if that's the thing where the spark comes from) to any of it's 4 output wires.

The sticky suggests that my coil needs to be replaced (#5) but a local mechanic (who i don't know) said it could also be the ignition module located in the distributor cap. For some reason distributor cap is quite oily.

As I cant get the boat to the mechanic for 2 weeks I was wondering if I should go ahead and replace my coil to see if that works or should I leave it to him to sort out.

Any suggestions would be appreciated.

Thanks,
Justin.

 

[cr2k]

Re: Ignition problem - no spark from coil

While it could be the coil, my money is on the ign module. But the coil is much cheaper to replace. If you know someone who has an ignition coil laying around (any ign coil will work for this) swap the wires over and see if it works. Then you will know if you need to buy the specific coil for your engine.

 

[Lyle29464]

Re: Ignition problem - no spark from coil

How did you by-pass the shift cutout?

 

[CobiaXL]

Re: Ignition problem - no spark from coil

I got boat with a 2003 Mercruiser 3.0 (SN OM664324) two months ago and all has been ok until this week when it didn't start. Here's what I know:

1. I don't get a spark from the ignition coil
2. I have bypassed the shift cutout switch
3. I get 11.5V to the ignition coil
4. I get 11.5V (on both wires) to the distributor cap
5. There is no continuity from the coil tower (if that's the thing where the spark comes from) to any of it's 4 output wires.

The sticky suggests that my coil needs to be replaced (#5) but a local mechanic (who i don't know) said it could also be the ignition module located in the distributor cap. For some reason distributor cap is quite oily.

As I cant get the boat to the mechanic for 2 weeks I was wondering if I should go ahead and replace my coil to see if that works or should I leave it to him to sort out.

Any suggestions would be appreciated.

Thanks,
Justin.

Whats the voltage at coil while cranking?

 

[GLENN M]

Re: Ignition problem - no spark from coil

take wires off neg side of coil.then with a piece of wire attach to neg side coil then with key on touch to ground,when you pull wire off ground you should get a spark out centre coil wire,witch you should have placed quarter inch from ground first, my fault,goodluck

 

[fat fanny]

Re: Ignition problem - no spark from coil

You also could be dealing with loss of connection to any of the components to the dizzy due to oil saturation. pulll the cap and module and clean it thouroughly with wd-40 or any other acceptable electrical cleaner and try again and wiggle all your contacts while checking before swapping out parts make sure you follow all the troubleshooting techniques in the service manual. Good Luck

 

[Silvertip]

Re: Ignition problem - no spark from coil

Checking for continuity between the coil tower and spark plug leads is of no value since there is no physical connection. The distributor rotor is in between the two points and the rotor inside the distributor never physically touches the plug wire posts as the rotor turns. While you may have power to the coil, an open coil primary winding would render the coil useless. Disconnect the small wire at the coil and measure the resistance from the terminal to ground. If it shows open, replace the coil.

 

[Don S]

Re: Ignition problem - no spark from coil

From the sounds of some of these replies, I don't think many know you have the EST distributor and coil setup.

here is a link to the OEM service manual.
http://www.4shared.com/document/xEKlzP-s/Service_Manual_26.html
Section 4B covers the ignition system and testing the components properly.

 

[juzza]

Re: Ignition problem - no spark from coil

Thanks for all the suggestions, I thought I had subscribed to the thread but didn't get any emails. Anyway, as per Don S post I tested the ignition components (thanks Don S) and it seems the coil should be replaced. More details below.

I dont have the tool required to test the ignition module so didn't do anything there. I tested the pickup coil and that seems fine (result from step 5 was 835 ohms). The Ignition Coil testing was done as below. There is no diagram in the manual for this test so I am assuming:

a coil tower (coil high tension post) (12 O clock)
b terminal connecting to purple wire ( 2 O clock)
c terminal connecting to grey wire (4 O clock)
d ground (coil frame)
e terminal connecting to distributor (8 O clock)
f terminal connecting to distributor (10 O clock)

Testing Ignition Coil
1. If not already done, disconnect wiring from ignition coil. Connectors are molded and
keyed to assure proper positioning. The terminal (e) feeds 12 volts to the distributor.
NOTE: Upon reinstallation, first install black connector (distributor harness) to coil. Then
install gray connector (engine harness).
***Done
2. Set ohmmeter to "Rx100" scale and connect one lead to 12 volt terminal (b) of coil and
the other lead to "ground" (d), any clean metal on the coil frame. Reading should be infinite.
If not, replace coil.
*** Infinite reading => coil OK.

3. Set ohmmeter to "Rx100" scale and connect to 12 volt terminal (b) and terminal (c).
Reading should be approximately .4 ohms. If not, replace coil.
*** Reading ~0.4 ohms => coil OK.

4. Set ohmmeter to "Rx1" scale and connect to 12 volt terminal (b) and tachometer terminal
(f). Reading should be approximately .4 ohms. If not, replace coil.
*** I'm getting 0.1 ohms to f (as I have named it) and 0.4 ohms to e. I might have these named incorrectly.

5. Set ohmmeter to "Rx100" high scale. Connect ohmmeter to 12 volt terminal (b) and to
coil high tension post (a). Reading should be between 7800 and 8800 ohms. If it reads
outside of this range, replace coil.
*** Infinite reading => Replace coil


I will replace the coil ($135) and see how it goes. I have another question, is it possible that an issue somewhere else could result in the ignition coil breaking? Should I check anything else before putting in a new coil?

Some answers to the responses above, thanks again to all:
cr2k: that would be nice but I dont know anyone who has a boat.
Lyle29464: Essentialy I connected the 2 wires that lead into the the interupt switch. Better description in the manual above.
CobiaXL: Not sure as I dont have a remote starter.
GLENN M: dont know where the negative side of the coil is
fat fanny: Have cleaned the dist cap and ignition module
Silvertip: I was testing from the tower to the terminals on the ignition coil, not sure what the correct technical term for these is. This was similar to the test steps above.
Don S: I wasn't even sure myself (didn't know what EST was) but thought it was EST as the wiring diagram for EST is closest to what I have. thanks for the manual

 

[fishrdan]

Re: Ignition problem - no spark from coil

3. I get 11.5V to the ignition coil
4. I get 11.5V (on both wires) to the distributor cap

I thought the EST ignition required a minimum 12V to fire? I could be wrong, but thought I read that somewhere,,, sometime...

I will replace the coil ($135) and see how it goes.

You can buy a complete EST ignition system (coil, dist, wires, etc) for $200.
http://www.michiganmotorz.com/delco-voyager-marine-electronic-distributor-p-120.html

Essentialy I connected the 2 wires that lead into the the interupt switch.

Whell, there's a problem... With the shift interrupt switch wires connected together the ingition is being cut off, by the wires being connected together. Under normal operation, the shift interrupt switch momentarily shorts those 2 wires together to cut the ignition (stumble the engine) and unmesh the drive's gears, so you can shift out of gear. Connecting them together all the time shuts down the ignition.

If you are timing the engine you need to short the shift interrupt wires,,, after jumpering the white timing wires on the distributor. Without the timing wires jumpered you are just killing the ignition.

Disconnect the shift interrupt wires and see if it fires.

Though, It sounds like the coil is bad from your testing. I didn't read through the testing you did, but it sounds like you found a bad coil.

 

[juzza]

Re: Ignition problem - no spark from coil

Thanks fishrdan,

I took the ignition coil to a repair shop, they tested it and said it's fine. I'm confused, my mutimeter still says there's no connectivity from the tower.

I have connected back up the interuptor switch (still no spark) but will also try disconnecting these wires. I've had enough if it for now

 

[Don S]

Re: Ignition problem - no spark from coil

I don't have a coil in front of me to check how and where you checked each item on the coil, and it looks like Merc left out a picture to clear things up.
So here is from a Volvo manual. Same ign. sys
Might want to verify your readings.
You also need to charge your battery, 11.75V indicates a dead battery and you will not get the engine started.

 

[fishrdan]

Re: Ignition problem - no spark from coil

You also need to charge your battery, 11.75V indicates a dead battery and you will not get the engine started.

Yup! that's what I'd do first.

Disconnect the shift interrupt wires and see if it fires.

I have connected back up the interuptor switch (still no spark) but will also try disconnecting these wires. I've had enough if it for now

Unhook the wires (make sure they are not going to ground out to anything, tape em' up) and see if you get spark. If the switch is bad (premenantly closed connection, or the switch tripped) it will still be killing the ignition. I kind of doubt this is the problem, but hey, it's only going to take 10 seconds to try it. You could also check the switch with your DVM, see if it reads infinity when at rest and near 0 ohms (1-2ohms maybe) when it's depressed.

 

[juzza]

Re: Ignition problem - no spark from coil

I removed the battery (I have a single battery) and charged it on multistage charger on trickle for several hours until it was fully charged.

At full charge the battery was reading 14.5V (I thought the max was 12.6V)
Left it disconnected overnight and it was reading 12.97V in the morning
Connected it to boat and it was reading 12.77
Disconnected the switch interrupter wires (thanks fishrdan!), was getting 11.68V between these.
Voltage coming into the ignition coil was 11.52V
Voltage coming into the ignition coil while cranking was 9.5V

Are these voltage drops expected? The first thing I did when I couldn't start the engine was to take the battery back to where it was bought. The guy there tested it and said it was fine.

If these voltages are ok it would seem that the problem is probably with the ignition module? Is there anything else I could test.

Thanks,
Justin.

 

[Formula sr1]

Re: Ignition problem - no spark from coil

I removed the battery (I have a single battery) and charged it on multistage charger on trickle for several hours until it was fully charged.

At full charge the battery was reading 14.5V (I thought the max was 12.6V)
Left it disconnected overnight and it was reading 12.97V in the morning
Connected it to boat and it was reading 12.77
Disconnected the switch interrupter wires (thanks fishrdan!), was getting 11.68V between these.
Voltage coming into the ignition coil was 11.52V
Voltage coming into the ignition coil while cranking was 9.5V

Are these voltage drops expected? The first thing I did when I couldn't start the engine was to take the battery back to where it was bought. The guy there tested it and said it was fine.

If these voltages are ok it would seem that the problem is probably with the ignition module? Is there anything else I could test.

Thanks,
Justin.

Justin did u ever figure this out the thread stopped and I'm right at this point now?!

 

[Don S]

Re: Ignition problem - no spark from coil

What's the difference if the OP figured out his problem or not. May not even be what is causing your problem. What you need to do is start a new thread of your own with your engine info along with what you have done. Then we can help you figure out YOUR problem.