454 starting trouble

[beached]

1990 carbureted 454 I/O with Thuderbolt electronic ignition... New to me this season, has run fine and without issue after some carburetor choke adjustments. But yesterday morning couldn't start it...

-engine spun fully, no battery problem.
-fuel sprayed from the carb jets, but no ignition...
-tried starter fluid, no change...

Didn't have my electric tester with me, but...
-pulled a spark plug wire and checked for spark, nothing...
-checked for arc at the distributor feed out of the coil, nothing, but I was overly cautious, as I've been zapped by coil issues during past auto repairs.

I will be back to the boat later this week and will have my tester, but what else should I take along? Other than a new coil are there any other things I could check to narrow down the problem?

thanks in advance

[ceteejr]

Sounds like the coil to me. First I reploced the coil on one engine & then the other. One engine wouldn't start & the other was running rough. I didn't replace them both at the same time, as I remember it was probably about a year apart.

[beached]

That's my first guess also...But since I'm going back to the boat in a couple of days, i figure I'd see if anyone has other possible recommendations from their experience also...
Aside from the coil, I already have a spare distributor cap on the boat... Anything else I might consider that would cause 'no spark' while the engine turns over?

thanks

[fountain-boy]

the eletronic pick up in the distributor. known for failing.

[THE BUZZARD]

Beached,

I presume you made sure the distributor shaft is turning . If you have a test light ground the light touch it to voltage make sure it is working. Key on engine cranking touch the positive side of the coil should have a solid light. If thats good go to the negative side of the coil with the engine cranking if the light pulses that tells you the module and pickup are good and you prob have a bad coil. No pulse on the negative side unhook the pickup at the module and ohm it for resistance I am not sure of merc's spec but am thinking in the 70-90 ohm range. If the pickup checks out ok the the module may be faulty. Hope this sheds a little light for ya!

Good Luck
Preston

[beached]

Thanks guys...
I'll be at the boat later today and will go thru the items you've recommended ... I will have a new coil with me just in case.

Thanks again.

[captcl]

Beached, also make sure your batteries are "up" and good. had a 454 crusader
(last of the carb series) in my old boat and it ALWAYS ran better on fully charged batteries.

[blackwell50]

check the adjustment of the shift interupt switch.

[beached]

Thanks for the input guys... worked on the boat over the weekend...Power to the coil and batteries fully charged, engine spinning perfectly... NO SPARK.
First of all...
I replaced the coil... no change.
I replaced the distributor sensor, while I was at it, because it had some corrosion and I put in the newer upgraded Mercruiser sealed replacement... no change.

I followed the Merc Manual troubleshooting recommendations as follows:

1. Checked all connections at distributor, coil and ignition amplifier... good.

2. Key in 'run' position, checked for power to the coil (+) terminal... good.

3. Checked for power at the 'red/white' terminal on the distributor... good.

4. Disconnected the 'red/white' lead to the dist and tested for power... NOTHING.

According to the Manual, it means the Ignition Amplifier needs replacement... Unfortunately, the local marinas didn't have in stock and couldn't get over the holiday weekend...

I'll be ordering that Amplifier tomorrow... Unfortunately, I only used a standard power tester (bulb type), without voltage readings.

Hopefully, that's it, but is there anything I could be missing? If I can't get her up and running on Friday, she'll get a professional to check her out.

Anyone have any 'trustworthy' Montauk mechanic they can recommend, in case? Mine's way west.

Thanks