No Spark

B

BillyT0020

New Member
Apr 11, 2008
263
Catawba Island
Boat Info
1980 260 DA
Engines
Merc 260
Hey Guys,
Having a no spark issue that I can't seem to chase down. I searched previous threads and tried the suggestions from past but nothing worked.

Splashed the boat last week, ran fine. Put in an ignitor electronic ignition conversion, ran even better. Came up to the lake this weekend and no spark. She won't even try to turn over. I figured the electronic ignition module went bad so I put the points back in but still can not get a spark to the plug (tested by pulling and grounding the base to the block. The coil is new this season, pertronix flame thrower, and I put a new rotor in. I bought a cheap mulitmeter to try and chase down where I was loosing spark but no luck. I had 5 volts hooked up to the pos and neg terminals on the coil with the key in the run position. I thought that was low so I hooked up a jumper wire from the positive side of the coil directly to the battery, no go. I put the old coil back on, still no go. This one has me stumped.

Any Ideas?

Thanks in Advance!
 
The first thing I would do is get good battery voltage to the coil. When you jumped the coil what was battery voltage? Next I would make sure coil is good ( chances of two bad coils are slim ) you never know. Check or change coil wire. Check or change small wire from dist. to coil. Check for complete circut between wire in dist. to coil. Make sure no wires in dist. are grounding out. Good luck!
 
thanks for the tips ill give them a shot in the morning. also was thinking it might be the shift inturupt switch, anyone know where its typically located incase i need to replace?
 
It's the microswitch on the shifter fork attached to the starboard side exhaust elbow.
 
Well I’m really stumped now. Today I went through just about everything and still no spark and at this point I’m just throwing parts at the boat hoping something works. I have put on a new distributor cap, rotor, coil, electronic ignition and then back to points. Jumped the coil with 12 good volts, took the shift interrupt switch and tach wire off the coil to try and bypass, cleaned all the connections and still nothing.

Could it possibly have something to do with the ignition key switch? The starter is turning the engine over and if the voltage was low from the key switch then when I jumped the coil directly to the battery then it should have provided the cap with spark to distribute. At this point the only thing I have tried are new wires and plugs but I don't see how the boat sitting for 4 days before running perfect would cause the wires to go out and the plugs were new last season and still look fine. An ignition system just isn't this complicated, or so I thought.

One thing I did notice that may provide a clue. When I put the aftermarket coil on, I noticed I had spark to the negative side of the coil when I initially touched the wires to the terminal, but now there is nothing. I would say the shift interrupt switch could be a possibility but when I took those wires off the coil the engine should have had spark.

Is there something stupid I’m missing? Starter Solenoid?
 
I don't think that the answer is going to be throwing parts at it until it runs. You mention no spark, but in another post you mention starter solenoid. Two completely different things. You need to start at the place where you have failure and work backward. If it is truely spark - engine turns and turns and turns but doesn't catch - work your way back to the ignition parts and fuel. If the issue is that the engine doesn't even turn over, start at the starter and go backwards. Get yourself voltmeter and happy hunting.
 
Yes the problem is no spark.Enine cranks but dosnt catch.I only mentioned the solenoid because I thought it mihg have some effect on the voltage to coil. But if it was simply low voltage it should have started when I gave it a full 12v from the battery.
 
I'm having a little trouble folling you, sorry. I think you have tested the coil to the distributor and that is fine. So juice is flowing that way. You swapped out the electronic ignition for your old points... What about the rotor? You noted that you changed it, but is it making contact with the cap? What about the cap? Probably not the cap if ALL cylinders aren't getting spark. Back to the cap. Are all of teh contacts good?
 
unlvrebel said:
I'm having a little trouble folling you, sorry. I think you have tested the coil to the distributor and that is fine. So juice is flowing that way. You swapped out the electronic ignition for your old points... What about the rotor? You noted that you changed it, but is it making contact with the cap? What about the cap? Probably not the cap if ALL cylinders aren't getting spark. Back to the cap. Are all of teh contacts good?
Click to expand...


Sorry if my posts were confusing. The Rotor is making contact with the cap because I can see the impression on the rotor, but the new rotor looked different the the old one so I tried the old one again and still nothing. The cap is new and all contacts are good.

The rotor is spinning inside the cap.
 
unlvrebel said:
I don't think that the answer is going to be throwing parts at it until it runs. You mention no spark, but in another post you mention starter solenoid. Two completely different things. You need to start at the place where you have failure and work backward. If it is truely spark - engine turns and turns and turns but doesn't catch - work your way back to the ignition parts and fuel. If the issue is that the engine doesn't even turn over, start at the starter and go backwards. Get yourself voltmeter and happy hunting.
Click to expand...


I am sure it is a spark issue and not a fuel issue. The boat has a brand new poly gas tank, new fuel pump, new hoses, new gas, new fuel filters, and it wont catch on starting fluid in the carb.
 
Is your engine "grounded"? Sounds like a problem that a buddy of mine once had after an engine swap (289) in a 65 Mustang. Wouldn't run at all. The ground wire to the block was internally broken. He added a braided ground strap and walla...

The fact that you ony get 5V at the coil points to a basic wiring, ignition switch, starter solenoid, or ground problem. The coil should get full battery voltage with the key on.

Good luck.
Michael
 
skibum said:
Is your engine "grounded"? Sounds like a problem that a buddy of mine once had after an engine swap (289) in a 65 Mustang. Wouldn't run at all. The ground wire to the block was internally broken. He added a braided ground strap and walla...

The fact that you ony get 5V at the coil points to a basic wiring, ignition switch, starter solenoid, or ground problem. The coil should get full battery voltage with the key on.

Good luck.
Michael
Click to expand...


Thanks for the suggestion Michael, that would be a very easy fix! Ill pick up a new ground wire from the block to the main battery just in case.
 
I doubt the ground cable is bad. The ground wire connect to the engine block. If the starter cranks, then the ground wire is OK.

This should be pretty simple to troubleshoot. First you'll need a good and accurate voltmeter. Don't care if it's digital or analog. This is stone age technology. Connect the negative lead of the meter to the block and touch the positive lead to the battery to ensure good connections. You should read at least 12.6 volts.

Remove the shift interrupter wire from the negative side of the coil. Believe that wire is brown. Connect the meter's positive lead to the terminal on the coil marked (+). This should have a purple wire. There should be zero volts with the key off and something less than 12 volts with the key on. You should not expect to see battery voltage with the key on since there normally is a dropping resistor in line between B+ and the coil, which reduces the running voltage. Typical voltage drop is about 1 or two volts. You should see battery voltage with the key in the start position as start bypasses the resistor.

If the voltage is not present at the (+) terminal with the key on, there is either a wiring problem or the ignition resistor is bad. You can determine if the resistor is bad by turning the key to start. If you now get voltage, the resistor is bad. The resistor is in the wiring loom. This does not cause a no-start problem, but troubleshooting in a systematic manner is better than throwing parts and guesses at a problem.

Before doing this step, ensure that there are no gasoline vapors present in the engine room! Remove the (-) wire from the coil. Hold the secondary lead from the coil close to the engine block. Turn the ignition on. Using a test lead, connect one end of the lead to the coil's (-) terminal and briefly tap the other end of the test lead against the block. You should see a spark from both the test lead, and more importantly, from the high voltage lead each time you tap the wire to the block. Replace the coil if you do not get this.

Reconnect the (-) lead. Turn the key to start and there should be battery voltage present at the coil. Remember that battery voltage will be lower with the starter turning. Meter battery voltage with the starter turning if in doubt about the measurement. If battery voltage is not read, then there is a wiring problem. If there is battery voltage at the (+) terminal of the coil, check the voltage at the (-) terminal while the engine cranks. There should be voltage, but less than the voltage read from the other terminal. Zero volts or battery voltage indicates that the wiring between the coil and distributor is bad, the points are bad, or the after market ignition module is bad, depending on which you currently have installed.

If you have a digital voltmeter with the ability to read frequency, switch to the frequency mode. Figure cranking speed of 200 rpm should give a frequency reading of something like 800 hertz. Zero Hz indicates that the wiring between the coil and distributor is bad, the points are bad, or the after market ignition module is bad, depending on which you currently have installed. You can also use an old-fashioned dwell meter here to do the same type of testing. No dwell reading indicates the same types of problems..
 
Thanks for the great write up! I have printed this off and will try everything you recommended until I find the culprit. I'm still not sure why any of the things I tried didn't work but oh well. I also bought new plugs and wires (the wires were due anyway and it doesn't hurt to have an extra set of plugs on board) to take with me this weekend and exchanged the Petronix Electronic Ignition and Flame Thrower Coil's for new ones just incase either went bad.

Im thinking its the wire from the coil to the distributor. Its the only thing that could have caused no spark to all cylinders that I didn't swap out or bypass. I also want to check the wires on the ignition key switch and clean the connections there incase I bumped something. If all this dosn't work Ill pay the mechanic to figure it out on Sat morning because I don't want to miss another weekend on the lake due to pure stubborness!

Thanks again.
 
I had the same issue. No voltage to the + side of the coil on my port engine. Used a jumer wire to the + side of the coil and it would fire right up. Checked the switch and it was good.

I was sitting with my son on the fly bridge drinking a beer (I really think this gave me brain power) looking at the switches and stuff. I noticed the a switch for each engine which was marked "off-run-start.":smt021

Yep, the switch was in the off position! Flipped it to run and yep, the engine fired right up.:wow:
 
AKBASSKING said:
I had the same issue. No voltage to the + side of the coil on my port engine. Used a jumer wire to the + side of the coil and it would fire right up. Checked the switch and it was good.

I was sitting with my son on the fly bridge drinking a beer (I really think this gave me brain power) looking at the switches and stuff. I noticed the a switch for each engine which was marked "off-run-start.":smt021

Yep, the switch was in the off position! Flipped it to run and yep, the engine fired right up.:wow:
Click to expand...

Yeah unfortuanatley when I hooked up a jumper wire to the positive side of the coil it still wouldn't fire. I have tried swapping everything, so Im guessing its the high lead wire from the coil to the cap. Its about the only thing I havn't changed out in the whole ignition system. We shall see!
 
Well, Not sure what it was but After I put it new wires, plugs, coil and Electronic ignition she fired right up. One of those components was bad. Oh well problem solved.
 
Not sure if this is relevent but, when I received a new MSD coil the instructions were adament about installing a ballast/resistor ( 8 ohm) in the hot wire going to the coil. The instructions said "system damage could occure" if I don't do this. Exactly what damage they don't say. You mentioned that you installed a different coil. I am assuming you meant a coil that puts out more voltage than the stock coil.
I'm just throwing this out since you are grasping for any straw at this point.
Good luck......jd
 
Thats a thought, if something goes wrong with the system again I will look into it but the petronix flame thrower coil is supposed to be compatible with the ignitor electronic ignition I used. The instructions didn't say anything about installing a resistor inline.
Thanks,
 
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