No spark

[stranded-sailor]

Hi all, back again trying to sort out this problem. Quick rehash; had my engine shut down, figured it needed a tune up as had no spark and plugs and rotor were bad looking. Replaced plugs, cap, rotor. Wires looked newer in ok shape and being broke opted to go without atm. Also replaced coil.. After replacing these parts engine fired right up and ran 20 minutes or so. Next day started and ran 5 minutes, shut off. no start, no spark. Engine is a '72. Switched to electronic ignition.. Any thought or direction would be appreciated.

[Dave Neptune]

Did you check for voltage at the "+" terminal on the coil?

Did you turn the ignition key off after the "20 minute" run or did it die?

Did you possibly leave the key on at any time?

Dave Neptune

[hanleyclifford]

I could bet the farm you fried that coil. EI will kill an unprotected coil way faster than points ignition. Voltage at coil+ must be held between 10 and 12 volts unless you have the Moyer coil. If not, get a resistor in front of the coil.

[ndutton]

Please read this thread in its entirety.

[stranded-sailor]

Did you check for voltage at the "+" terminal on the coil?

Did you turn the ignition key off after the "20 minute" run or did it die?

Did you possibly leave the key on at any time?

Dave Neptune

Hi all, sorry not to be right back to you on here, been dealing with some boat problems.
So there is voltage at the coil +.My battery is a little low right now as I tested it but only got 10.5v at the coil,, battery is at 11.8.
After the 20 min run I shut it off with the key. Next am ran for 5 minutes than quit. The key hasn't been left on.

[stranded-sailor]

I could bet the farm you fried that coil. EI will kill an unprotected coil way faster than points ignition. Voltage at coil+ must be held between 10 and 12 volts unless you have the Moyer coil. If not, get a resistor in front of the coil.

I just checked resistance in the coil and I think you may win the farm. Being new with only a couple hours on it i didn't want to believe that was it I guess but I'm getting no resistance between the center pole and either + or -

[hanleyclifford]

Hi all, sorry not to be right back to you on here, been dealing with some boat problems.
So there is voltage at the coil +.My battery is a little low right now as I tested it but only got 10.5v at the coil,, battery is at 11.8.
After the 20 min run I shut it off with the key. Next am ran for 5 minutes than quit. The key hasn't been left on.

The important voltage is when the engine is hot and running with alternator functioning normally. It should not exceed 12 volts at coil+. This means the coil must be running well below system voltage originating at alt+. The differential can be achieved by putting resistance in front of the coil (which can be a cheap automotive coil) or by getting the Moyer coil which has the resistance internal. I looked at the Pertronix information which seems to suggest 4 amps is ok at the coil. My engine runs great at 1.25 amps and 10.5 to 11 volts.

[stranded-sailor]

Hi all. I've found a napa ic14 coil i can get but the parts store here in Canada aren't real smart and he can't even tell me the resistance in this coil. Does any one know if and what size resistor I would need plz? I've tried looking it up but my internet is so bad its taking me 5 minutes just to get a post to upload

[hanleyclifford]

It is hard to find idiot proof parts stores so you usually have to assume the worst. It might be necessary to buy a resistor to put in front of the coil. If the engine will not start with the resistor in line that could mean the coil already has sufficient internal resistance. This is the hard way to do it but it is idiot proof. Descriptions of parts online seldom include the truly useful information. Put your voltmeter on coil+ so in the event the engine starts you will have a good voltage reading right away, The other option is to spring for the Moyer coil which has it's own internal resistor.

[Dave Neptune]

If the coil is for a four cylinder engine you should be OK. I used a coil off of an old VW for quite a few year with an EI I adapted to my A-4 before they became available for the A-4. A 6 or 8 cylinder coil will not last as long because they are designed for shorter saturation times. Get a resistor and a 4 cylinder coil then check the voltage at the positive post of the coil after the engine has run for a bit so the alternator is not charging heavily IE the batteries are charged and output is just maintaining voltage.
As long as the coil does not see much over 12.5 volts pretty much any 12v coil will work.

Best bet is just get the coil and resister from our host and be done with it. And do remember to keep the key OFF when not running or after diagnosing if you need to turn the engine. When I am working on an engine and need to turn it over I always disconnect the coil positive side.

Dave Neptune

[joe_db]

My oil pressure alarm will let me know quite loudly if the ignition is on and the engine is not running

[Sam]

Hi all. I've found a napa ic14 coil i can get but the parts store here in Canada aren't real smart and he can't even tell me the resistance in this coil. Does any one know if and what size resistor I would need plz? I've tried looking it up but my internet is so bad its taking me 5 minutes just to get a post to upload

I urge caution with that coil. if your using EI. The NAPA IC14 coil is what I run fine with for years with points [early model Prestolite distributor.] Been a few years since I measured resistance but remember it as 3+ ohms something measured across the terminals. A few years back a friend's boat converted to EI without changing coils and in a short time cooked the coil. All of this was thoroughly discussed and was extremely informative on posts about a dozen years ago. For EI i think you want a coil with about 4 ohm internal resistance, [I remember one post by Neil D where he cut an old coil apart and there was no internal resistor piece - resistance is determined [engineered] by the wire resistance and length of the windings] At least that is what i recall.

[ndutton]

You recall correctly Sam.

https://www.moyermarineforum.com/forums/showpost.php?p=117604&postcount=301

Be careful not to get myopic about coil resistance or system voltage alone. As explained in the Pertronix treatment I recently posted, they work in tandem and their quotient is critical to a reliable electronic ignition system.

[stranded-sailor]

If the coil is for a four cylinder engine you should be OK. I used a coil off of an old VW for quite a few year with an EI I adapted to my A-4 before they became available for the A-4. A 6 or 8 cylinder coil will not last as long because they are designed for shorter saturation times. Get a resistor and a 4 cylinder coil then check the voltage at the positive post of the coil after the engine has run for a bit so the alternator is not charging heavily IE the batteries are charged and output is just maintaining voltage.
As long as the coil does not see much over 12.5 volts pretty much any 12v coil will work.

Best bet is just get the coil and resister from our host and be done with it. And do remember to keep the key OFF when not running or after diagnosing if you need to turn the engine. When I am working on an engine and need to turn it over I always disconnect the coil positive side.

Dave Neptune

Tks for the great info. I agree a proper coil from our host would be best but I'm in Canada and they can't promise shipping charges, in fact they warn that it could be substantial cost at border. Ya Canada! Not!!

[joe_db]

Maybe this or similar?

https://www.amazon.com/Standard-Motor-Products-UC15T-Ignition/dp/B00809W952/ref=cm_cr_arp_d_product_top?ie=UTF8

I think this is what the local shop gave me. Mine has been working fine for years, but read the reviews, seems like maybe they shifted to China and the newest ones haven't been as good?
* I feel your pain with customs, all my canvas is from Genco in Toronto and it went back and forth a few times for alterations and both countries kept trying to charge me duty both ways