coil question (1973 johnson 50 hp) calling all ignition gurus

[hotshot123]

ok, first off i will tell you all that i have no fire at all. this motor sat inside a closed garage for the better part of 30/35 years. everything seems fine, good compression and all the basics other than it has no fire. ive disconnected the kill wire at the power pack and it still wont fire. at first i had about 350 volts coming in to the pack but nothing on the coil side. i then took every terminal i could find and cleaned it all to endure everything was getting good contact. re-try coil side and my meter is getting something now but its hard to tell because i dont have a dva. anyway, i looked online and found this instruction for checking coils. the short version says:

1. says a good coil should have continuity across the 2 (orange) wires- im good here. my meter flashes and goes to zero just like touching the meter leads together

2. it says a good coil should read 3000 to 8000 ohms from the secondary winding (one of the small ones but im not sure witch one) to the spark plug end - not so good here because i dont get anything from either small wire to the spark plug connector

My question i guess is, are these directions for checking accurate? if so it would seem that i have 2 bad coils that went bad while sitting up for a long long time. Also, im checking this off the motor. the coils are sitting here on my desk at work.

here is a pic of the the type of coil im dealing with.

 

[F_R]

Re: coil question (1973 johnson 50 hp) calling all ignition gurus

There should be resistance reading between the spark plug wire and ground wire. Not sure how many ohms though. I suppose several k-ohms.

BTW, you can't check the power pack output wth a multimeter. Need a DVA for that.

 

[hotshot123]

Re: coil question (1973 johnson 50 hp) calling all ignition gurus

thanks man, yeah i knew i would need the dva and should have one tommorrow. It looks like I got 2 bad coils either way because there is nothing between the ground wire and spark plug boot. this fancy fluke meter i got from my buddy is really touchy. i get a reading of "some" ohms just holding the leads in my hands but ground wire to boot is like not even making the the readout flicker at all.

 

[hotshot123]

Re: coil question (1973 johnson 50 hp) calling all ignition gurus

jumped the gun, after getting the boots off, those ends were corroded so bad my meter wasnt making contact. now from the ground to the spark plug wire there is resistance but the 2 coils read totall different. one is straight continuity and the other throws a bigger number up in the 300's. I might try to take a couple of pics and see if anyone can deduce which might be good or not.

 

[boobie]

Re: coil question (1973 johnson 50 hp) calling all ignition gurus

After you get your DVA, check the voltage out of both the stator and the timer base. If these are okay you may have a a bad power pack.

 

[nwcove]

Re: coil question (1973 johnson 50 hp) calling all ignition gurus

unscrew the wires from the coils, test them from the "prong" that the wire screws onto. ( or remove the wires, clip 1/2 inch off re-install and retest....have a good look at the "prong" in the coil(s), just to make sure its not rusty)

 

[hotshot123]

Re: coil question (1973 johnson 50 hp) calling all ignition gurus

one prong was completely rusted (real thick rust) and the other one looked shiney and new

unscrew the wires from the coils, test them from the "prong" that the wire screws onto. ( or remove the wires, clip 1/2 inch off re-install and retest....have a good look at the "prong" in the coil(s), just to make sure its not rusty)

 

[F_R]

Re: coil question (1973 johnson 50 hp) calling all ignition gurus

thanks man, yeah i knew i would need the dva and should have one tommorrow. It looks like I got 2 bad coils either way because there is nothing between the ground wire and spark plug boot. this fancy fluke meter i got from my buddy is really touchy. i get a reading of "some" ohms just holding the leads in my hands but ground wire to boot is like not even making the the readout flicker at all.

Just FYI, it is reading the resistance of your body. That's a good thing, instrument is working as it should. That is why you should never touch the leads when checking resistance---your body resitance will parallel the resistance you are trying to measure.

 

[hotshot123]

Re: coil question (1973 johnson 50 hp) calling all ignition gurus

my buddy still hasnt came through with the dva adaptor but, i was reading about this fluke 87-V that i have, and it claims to be one of only about 3 multimeters made that are fast enough to catch the reading. if the dva dont show up tommorrow, i am going to see how good this fluke 87 is. i would do it righ now but im sitting in the house with a sick kid and because of dr's orders, i cant leave him alone for even like 5 or 10 min. (ive got to collect "sample's" if he gets the urge) ewwwwwwwwwww. too cold outside anyway but tommorow it should be nice out and mom can stay on toilet patrol. hahahaha

Bty, if i do use the fluke on th powerpack, it is AC in and out, right?

 

[fstorm08]

Re: coil question (1973 johnson 50 hp) calling all ignition gurus

my buddy still hasnt came through with the dva adaptor but, i was reading about this fluke 87-V that i have, and it claims to be one of only about 3 multimeters made that are fast enough to catch the reading. if the dva dont show up tommorrow, i am going to see how good this fluke 87 is. i would do it righ now but im sitting in the house with a sick kid and because of dr's orders, i cant leave him alone for even like 5 or 10 min. (ive got to collect "sample's" if he gets the urge) ewwwwwwwwwww. too cold outside anyway but tommorow it should be nice out and mom can stay on toilet patrol. hahahaha

Bty, if i do use the fluke on th powerpack, it is AC in and out, right?

The only thing worse that taking care of a sick kid is when your sick yourself

The motor will be there waiting for you when you can get to it.

Hope your kid feels better soon

 

[Blacksting]

Re: coil question (1973 johnson 50 hp) calling all ignition gurus

Hotshot123,.....i recently bought a pair of coils for my '73 40hp johnny and came to find out i only needed to clean and regap ( .020 )the points . I paid $40 for em and you can have em for $20 plus shipping . let me know , btw hope your kid is doing better , i've had my share of looking after a sick child but never had to do the dirty deed you did .

 

[hotshot123]

Re: coil question (1973 johnson 50 hp) calling all ignition gurus

thanks blacksting, i will let you know something whenever i get to work on her again. my kid is going through some rough stuff right now and i have just set that project aside for a couple of weeks. I will beep you if i do see a need for the coils but more than likely i will take em. I need to research if they will work tho because my motor does not have points so im not sure of the difference in the coils