No spark with a tester but spark at the plug ????

rodknee1231

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I have a 1973 rude 135 I'm trying to get going. It has a new power pack and 4 new coils. I'm chasing a spark issue so I put a inline test light and a gap tester on my plug wires with nothing showing. So just for fun I pulled out the spark plug and held it against the head to see if it would spark and it did. Also the other day when I went to start it I got shocked through the key and while the wife was cranking it I got shocked through the plug wires. I figured I'd have a poorly grounded motor but when I use a ohm meter I have 0 resistance all over the motor. Any one who can point me in the right direction it would be appreciated thank you
 

gm280

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Okay, I think I know why you were not getting a jump across the spark gap tester.

When you installed the inline test light AND the spark gap tester, it was more then the high voltage could jump across. And that is because the typical inline spark light is usually a neon type bulb. And it takes, at the very least, 90 volts or more to ionize the neon gases inside the neon bulb to flash. And neon bulbs, usually a NE2H type, doesn't allow much current flow through them. But you also installed the gap tester as well. And with the both of them, it couldn't jump or pass enough current and voltage with all that resistance. I would try one or the other at one time, but not both.

See if that works better and come back and let us know. JMHO
 

rodknee1231

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I should have clarified I didn't use them both at the same time. One at a time
 

F_R

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It should have a lot stronger spark than that. Also, you won't catch me touching a spark plug wire when it is live. I hate getting shocked.
 

gm280

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I should have clarified I didn't use them both at the same time. One at a time

Okay that is a different story then. I honestly thought from reading your comment that you installed both at the same time and didn't get any spark. My fault! :facepalm:

Since you didn't get spark using either setup, you have some weak spark coils. If this engine uses points and condensers, it could be time to replace them and even the exciter coils, if that is how your engine is setup. With an engine that old, if the spark coils show any signs of cracks or even being heated, I would replace them as well. There are known to break down over time.

Other then those suggestions, there really isn't much else that could be causing your weak spark problems. JMHO
 

rodknee1231

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That's what I thought but when the plug is out and grounded it has a nice blue spark
 

rodknee1231

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Okay that is a different story then. I honestly thought from reading your comment that you installed both at the same time and didn't get any spark. My fault! :facepalm:

Since you didn't get spark using either setup, you have some weak spark coils. If this engine uses points and condensers, it could be time to replace them and even the exciter coils, if that is how your engine is setup. With an engine that old, if the spark coils show any signs of cracks or even being heated, I would replace them as well. There are known to break down over time.

Other then those suggestions, there really isn't much else that could be causing your weak spark problems. JMHO

All 4 coils are brand new all 4 have 0 resistance doing the same thing
 

gm280

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All 4 coils are brand new all 4 have 0 resistance doing the same thing

When you say zero resistance, exactly where are you measuring things. I mean point to point and if they are connected up or not. The only true way to verify anything correctly is to have it disconnected out of the circuit. So if your coils are connected to the ignition pack under the flywheel, disconnect those wires to read the primary and secondary sides of the the coils. Then reread them and let us know the resistance on the primary, secondary and the ground as well from both sides.

I am assuming your engine model number is 135ESL73M. Since that is the only 135HP model number I've found for 1973. It has a timer base with sensor assembly and a power pack and then four spark coils. It also have a 6 amp stator assembly with a rectifier for charging the battery.

If your primary winding read zero resistance, meaning a short, then your power pack could be the problem. But that remains to be determined yet. See what your coils read disconnected first. I will say it is pointing to the power pack presently being how you stated all four spark coils are new. And the odds that all four have gone bad at the same time is really remote.

Oh, when reading the primary side of the spark coils, use the R X 1 scale if you meter doesn't auto range because those reading could be very low. And the secondary side use R x 10 or even R X 100 or higher. JMHO

.
 

racerone

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???---No points and condensers on BIGGEST JOHNSONS since 1967 models.----Nothing like that on a 1973 135 HP motor !!!---Has the starter motor been tested ?
 

Faztbullet

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Check starter for proper RPM as Racer posted and check charge coil to pack voltage as weak going in will be weak coming out
 

F_R

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Leaking charge coils under the flywheel were very common on the 1973 models. Nearly all of them did. So if the originals are still in there, there ya go.. On that same idea, if the charge coils are weak, it will have spark with the plugs out, but maybe not with them in. Even with new charge coils, it has to be cranking a minimum of 200 RPM to make a useful spark.
 

rodknee1231

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When I ohm the coils individually the are at 0 on both wires. And just have the power pack sent out for inspection to make sure it was ok. Like I said they plugs spark when the pulled out the engine and grounded. But when they are in the engine and I use an inline tester I get nothing. Quite peculiar. I don't think it's a coincidence we got zapped I think there is a ground issue but I'm not sure. Also how could I go about checking the triggers and starter ?
 

F_R

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When I ohm the coils individually the are at 0 on both wires. And just have the power pack sent out for inspection to make sure it was ok. Like I said they plugs spark when the pulled out the engine and grounded. But when they are in the engine and I use an inline tester I get nothing. Quite peculiar. I don't think it's a coincidence we got zapped I think there is a ground issue but I'm not sure. Also how could I go about checking the triggers and starter ?


What I just said. If the charge coils are weak or if it is cranking too slowly you may have spark with the plugs out but not with them in. That is because it cranks faster with them out. That motor should produce a 7/16" spark with ease--that's enough to knock your right out of your boxers.

Your 4 new coils probably are ok. You can't expect "normal" resistances on them. Your meter may not be giving you true readings.

As for the key shocking you, it is a good bet that the key switch is arcing internally. There is 300 Volts in that switch. That same arcing might also be why you have no spark at the motor. Replace the key switch.
 

oldboat1

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Seems like you could do a simple continuity test on the starter switch (battery disconnected, and access to switch terminals). Think I would clamp a probe to the power terminal (purple wire, probably), turn the key to start and touch the other probe to a couple of locations on the switch housing. If there's continuity, think the switch ist kaput. Like F_R suggests, an internal short like that would be like connecting the M terminals -- would short out the ignition. Just for grins, could connect one lead to the power terminal and the other to an M terminal. If you show continuity that way or when you turn the key to the start position, there would be an ignition short in regular operation.

Anyway....think that's right.
 

F_R

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Well the idea is sound---but. You are dealing with high voltage on the black/yellow stripe kill wire here. The high voltage can arc across a gap where your continuity tester won't.
 

rodknee1231

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Well I found some corrosion on a negative cable where it mounts to the block I'll replace that first. To try to rule out the ground wire being bad. As far as the motor turning faster with the plug out that does make sense.
 

rodknee1231

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Would a regular battery crank the starter faster than a deep cycle? That's what I have been using for my cranking battery
 

oldboat1

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If same rating and condition, don't think it would matter. Cable corrosion wasn't the problem?
 

rodknee1231

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If same rating and condition, don't think it would matter. Cable corrosion wasn't the problem?

Haven't had time to replace the connecter the wire inside the connecter on the end was bad so I just cut it off and will put a new one on tomorrow. Also I'm gonna crank it with the gap tester clipped to the head or a ground wire and pull out the plug and see if it sparks to see if it is in fact producing a spark by turning faster
 

rodknee1231

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So I replaced the negative connection at the power head. Sounds like it's turning a little faster but the battery discharges kinda fast. Also I got to looking at my solenoid. Should it be grounded straight to the block ? It's connected to a black wire on the big red connector harness. Otherwise I'm gonna start looking into my starter.....
 
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