Plug wire connection

[Buplaux]

I have a 1974 johnson 135. Hopefully this can help someone else. I believe the design of the plug wire end connectors that attach to plug are a poor design. I belive it leads to failed coils due to higher resistance because of the scetchy connection of the little pin that just sticks into the plug wire. I had two new coils fail with a cracked plastic cover which is caused by excessive heat in the coil which is caused by the coil working too hard to overcome the reaistance. Ohm checked the wire and noticed the gauge went to infinity if I moved the wire at all. Ended up being the the little spring with needle connection issue. I replaced them all with crimp on automotive connectors (much more of a possitive connection) and had no more coil problems! Too me this is probably why so many people have coils failing, imo.
I was really surprised to see such a flimsy design when I removed the boot. Other than that the motor is impressive in its design, simplistic but effective, and runs great for such an antique

 

[racerone]

But they have used that design for some 60 years or more.--------It is therefor not a bad set up !!

 

[F_R]

I have a 1974 johnson 135. Hopefully this can help someone else. I believe the design of the plug wire end connectors that attach to plug are a poor design. I belive it leads to failed coils due to higher resistance because of the scetchy connection of the little pin that just sticks into the plug wire. I had two new coils fail with a cracked plastic cover which is caused by excessive heat in the coil which is caused by the coil working too hard to overcome the reaistance. Ohm checked the wire and noticed the gauge went to infinity if I moved the wire at all. Ended up being the the little spring with needle connection issue. I replaced them all with crimp on automotive connectors (much more of a possitive connection) and had no more coil problems! Too me this is probably why so many people have coils failing, imo.
I was really surprised to see such a flimsy design when I removed the boot. Other than that the motor is impressive in its design, simplistic but effective, and runs great for such an antique

I totally appreciate your opinion and conclusion. I suspect you have some electronics background? And yes, faulty connections within the plug boot certainly to cause arcing and burning within the boot, which makes the connection even worse. However, I'm not convinced that it is the cause of coil problems unless the situation has gone completely south. But I'll think about it.

BTW, proper installation of the boots does not rely on the pin only. The wire is supposed to be stripped 1/8" and flared out to contact the spring also.

 

[Crosbyman]

…..The wire is supposed to be stripped 1/8" and flared out to contact the spring also.


Interesting point … never seen that but very logical

as to automotive type booth crimps…. well anyone can have issues but it all comes down to poor work practices sometimes

My brother's John Deere tractor purchased "like new" … but "used a bit" had a rough engine performance ...

a quick ohms check from booth to coil showed the problem quickly … infinity

measuring ohms from the booth to a few pokes in the wire narrowed it down to a bad crimp job on the booth end clip . We opened it up recrimped it and no more problems since

I'll keep reusing the pointy springs and…. frared out 1/8 inch … maybe 3/16 ​

 

[racerone]

It might show infinity on a meter -----But spark on one of these can jump a gap of 1/2" or more.------Your " infinity " meter can not jump a gap like that !!

 

[Joe Reeves]

I believe the design of the plug wire end connectors that attach to plug are a poor design. I belive it leads to failed coils due to higher resistance because of the scetchy connection of the little pin that just sticks into the plug wire.

1974 is now 45 years back.... Coil failure depends a lot on exactly how old those coils are. However, whatever the cause of failure, the design of the connection is perfect more-so than what you have improvised for the vibration involved and I strongly suggest you switch back from what we in the trade refer to as a Mickey Mouse repair. The pin portion of the spring is normally punched through the inner wire of the HT lead...BUT... that is not the intended continuation of the voltage, rather the pin's purpose is simply to keep the spring connector where it belongs.See the proper method for the HT lead connection as follows.

"The rubber boot, spark plug end.... With the wire cut to the length required, trim back 1/4" insulation again but do not solder tint the wires. Simply fan out the wires and fold them back against the insulation, cutting the excess off as explained above. Holding the spring wire terminal, estimate where the prong should be inserted so that the spring will be flush against the exposed wire. Hold the spring terminal away from the wires end (sideways) and insert the prong into the insulation and into the center wire, then swing the spring terminal in front of the exposed wire portion (makes a tight fit for continuity purposes).

Spraying the inner portion of the boot where the wire will insert with a small amount of WD40 makes the installation of the wire a easy project. That's it".

 

[Crosbyman]

It might show infinity on a meter -----But spark on one of these can jump a gap of 1/2" or more.------Your " infinity " meter can not jump a gap like that !!

agree but infinity was certainly an issue on his john deere here because the problem was resolved when I got rid of it by recrimping the clip and inner conductor .

the initial crimp had not fully punctured the outer insulation to my liking anyway and the inner conductor had not been folded back under the clip.

btw JD uses carbon fiber wires for some reason

 

[racerone]

Infinity meters will find a broken wire ( gap in a wire ).-----When a 40,000 volts charge from a coil encounters a gap like in a sparkplug it jumps that gap.

 

[oldboat1]

Buplaux, are you using solid core wiring (7mm solid core)?

 

[Buplaux]

The stripping and fanning wire against the spring coil would certainly help(mine were not like that). Id be surprised to see these connectors on later model engines but I dont know. Still dont believe its a very positive connection, just my opinion. Striping, folding back, and crimping with dielectric grease seems more substantial and a more positive connection to me. My wires are stranded wire core btw. Its been pretty fun getting this old girl running smooth again (timing was way off as wel). Previous owner had many things screwed up, including choke linkage not allowing butterflies to close (hard starting), timing jacked up(bad idle), plugs gapped wrong, bad coil, bad plug connectors, etc... It screams now!
Ive also read through about 200 pages on this forum too

 

[Buplaux]

I totally appreciate your opinion and conclusion. I suspect you have some electronics background? And yes, faulty connections within the plug boot certainly to cause arcing and burning within the boot, which makes the connection even worse. However, I'm not convinced that it is the cause of coil problems unless the situation has gone completely south. But I'll think about it.

BTW, proper installation of the boots does not rely on the pin only. The wire is supposed to be stripped 1/8" and flared out to contact the spring also.

Thanks for the reply. The flare makes a lot more sense, mine were not like that. They obviously work but still dont see how properly crimped on connectors could be considered worse?
I fly a business jet for a living but have been turning wrenches for most of my 46 years

 

[racerone]

Yes , you do not know !!-------They were still using the very same bits in 2005 models.----Nothing wrong with the design !

 

[rothfm]

Bit of a hijack, sorry but applicable to the conversation above.

Speaking of this type connector....I was going to make some 0 resistance wires myself with HEI type connections.

Do you guys know if the pin type spring connector is available as a stand-alone item? Made-up wires are pricey. I still want to make my wires, have boots....Just need the little spring connectors. What are they called?

 

[F_R]

I've never seen the springs offered separately. That doesn't mean they don't exist though. Normally, they are sold with the boot, part number 581027 (18-5750)

 

[Crosbyman]

https://www.ebay.com/itm/Genuine-Joh...SXS:rk:16f:0

https://www.ebay.com/itm/POULAN-SPAR...nnu:rk:19f:0

https://www.ebay.com/itm/NEW-OMC-OEM...etm:rk:30f:0

 

[Joe Reeves]

Do not start replacing connections and components on that business jet (Lear?) that you may disagree with... the consequence is somewhat different.

 

[racerone]

Well said Joe------I can't believe someone working on his first motor would scoff at something that has been used for over 60 years !!

 

[Buplaux]

Well said Joe------I can't believe someone working on his first motor would scoff at something that has been used for

this is by far not my first motor. Entitled to my opinion. May very well be a fine design. Things change and technology can improve old designs with better ones.

 

[Buplaux]

Do not start replacing connections and components on that business jet (Lear?) that you may disagree with... the consequence is somewhat different.

Citation Excel. Nope I dont touch it Some of the designs on turbojet engines are just friggin genius!