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Ignition problem diagnosis needed

T

thelasthour

Member
"350 300hp carbed with ballast

"350 300hp carbed with ballast resistor. My problem started last month and has now gotten worse. Last month I could only start the boat cold if I temporarily "bridged the posts" in the ballast resistor. Jeff concluded that the starter solenoid may be having a problem. Yesterday I did my normal "bridge" and it blew the fuse on the ignition. I replaced the fuse and tried it once more and blew the fuse again. I removed my "bridge" and replaced the fuse with no more fuse blowing, but still no start. The engine would consistently start for 1 second. I assume it is not getting power to the coil in the "run" position and only in the "start" position. My second observation is that the buzzer alarm was not "sounding" in the normal key position of "run". It would begin sounding in the key position of "start". When i moved the wires under the key switch in the "run" position i would get sporatic buzzer alarm. Does this mean the key switch itself is causing all of this? I did not have a volt meter with me, so I could not diagnose further. I'm thinking the key switch has failed in the "run" position. Any other theories would be appreciated.
STeve"
 
"Could be a wire, a connector,

"Could be a wire, a connector, or the switch.

You've found the fuse in the ignition lead so that can be ruled out.

You can test the switch theory by jumper clipping the red to the purple lead (BAT to RUN). As it cranks, the battery feed is ok as is the starter lead coming back to the engine.

A test light would be good to verify excitation on the coil with the key on and during cranking.

You said it "starts" for 1 second...I'd say the ignition feed from the solenoid is fine. Your 'no buzz' with key on run is also consistent with the switch not passing current in RUN. I'd bet the buzzer is consistent with then '1 second' of engine run time. May be the switch.....

Your purple lead could also be corroded or broken inside of its jacket. The "wiggling" may have been enough to make the connection.

Final thought, the test light would be better than the voltmeter at resolving the issue. That's because it requires a reasonable amount of current to turn the bulb on. The mmeter will just show the voltage and not give you any indication of the ability to pass current."
 
"Update, on this still difficu

"Update, on this still difficult issue. After listening to all of the advice about my ignition, and my ballast resistor and coil I tried this... I replaced the ignition switch and my engine alarm sounded every time like it should and I was getting consistent power to coil, but still thru a ballast resistor. Still trouble to start, but it would start eventually. Then I swapped coils with one with an "internal resistor" and skipped my ballast resistor. Better start, but not consistent. I still killed my battery with too many attempts to start, after it cooled back down. When I called Crusader they recommended changing plugs to mr43lts, instead of the "platinum" ones I have now. They said the platinum plugs are harder to start. I'm also worried maybe my starter going bad and is "overamping" and creating a low voltage situation to my new coil since my battery is dying after about the 6th attempt to start the engine. Any thoughts?"
 
"I hear no mention of which ig

"I hear no mention of which ignition system this is.
And is there a reason you aren't using your VOM in your P of E (process of elimination)?
If I were diagnosing this, I'd be going right down a list and either eliminating or determining probable causes!

As for the ignition key switch "ign" side.....? It is possible that it has lost continuity. Use the P of E here also!"
 
"Had this very problem last sp

"Had this very problem last spring. The engine would start then cut out. Ended up being a failed crimp connection the purple lead between the coil and the ballast resistor.
When it first occurred I disconnected the resistor and joined the two leads together as a test. I still had the problem.
I ended up going through the current flow from the service manual step by step. When I got back to the purple wire on the resistor, I pulled on it the wire instead of the crimp. Well, this time the crimp stayed on the spade and the corroded wire came off in my hand. 30 seconds later the engine ran fine on the newly crimped wire."
 
"Hi Gang,
I have a similar pr

"Hi Gang,
I have a similar problem. I'm wondering whether the ignition switch is supposed to supply current to the coil when cranking or does the coil receive it's current when cranking from the I terminal on the starter solenoid? . According to the wiring diagram the I wire from the starter solenoid does'nt bypass the ballast resistor, it is connected to the same terminal as the IGN run wire. Same carbed motor with a Mallory electronic ignition. Any thoughts on this?

Thanks, Jon Allen"
 
"Jon:

the ignition switch w

"Jon:

the ignition switch will supply current during cranking. Whether that is sufficient for the coil/trigger to fire during cranking is driven by your specifics.

The I terminal on the starter's solenoid provides a means to minimize the voltage drop during cranking. It was key to reliable starting when engines used points. With all the different electronic ignition variants nowadays, "it depends" is the best answer without more information.

If it is an ALL stock configuration, I'd go with the factory wiring diagram and follow the troubleshooting procedures there. Mallory has some good debugging info on their www site if you have the specifics for the ignition system. (some setups are "happy" with the starter bypass ignition feed supplying the trigger module.)"
 
Hi Mark
Thanks for your respo

Hi Mark
Thanks for your response and info. I guess that taking 12v off the starter motor and supplying it to the ballast resistor would result in less of a voltage drop than taking it off the ignition switch. This now makes sense to me since the wire from the starter is not bypassing the resistor. As a result there will still be more power at the resistor due to the lessened voltage drop. I will check for voltage at the I or R terminal of the starter while cranking. This of course will be done with a conventional test light and a voltmeter.
Thanks Again
Jon Allen
 
"Not more power but higher vol

"Not more power but higher voltage at the resistor. I haven't done mallory stuff in a while but I remember putting in a few conversions where the IGN lead had to feed the sensor directly with +12V. Again, check with Mallory on the specifics. And when it comes to checking for voltage drops, a bulb will only show you gross ones; a high impedance meter is a better choice."
 
"Hi Mark,
The reason for the

"Hi Mark,
The reason for the conventional test light is not for checking voltage drop, its for checking amperage. You can have 12v at an electrical device, even if that 12v is being supplied by one fine strand of wire, say one out of 50 strands on a 16 guage wire. A digital meter will show voltage but one wire strand can't carry enough amperage to actually do much or light a conventional 12v test lite.. It probably will light a high impedance 12v test lite however. I avoid this style of test light unless I'm checking sensitive circuits or control modules. This type of light is less likely to cause damage to the aforementioned

Thanks Again,
Jon Allen"
 
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