Spark Plug wire Johnson RDE-19 1957 35hp

[frankr]

Contrary to popular belief, the low voltage does not pass through the ground to crankcase. But the high (spark) voltage does. Since it is several thousand volts, it has no problem overcoming any resistance in the rotating base connection.

[vintin]

Interesting Frank.

My mag plate has a little play in it.

I remember R.C. mentioning that some of the racers do run a separate ground wire. I believe I might.

[vintin]

To follow up on my project. I did find a problem. On one of the coils the spark plug wire seemed to be missing almost a whole half inch of center conductor where it screwed onto the post in the coil. I don’t know if this Belden Electotemp Ignition Cable (J) 4085 was OEM or not. I replaced it with this wire that Ben D. says he uses. $.69 per ft. http://www.oreillyauto.com/site/c/detai … yword=mw11

Interesting about the two coils. The green section on each one has a slight movement on the iron laminated section. I was able to pull the whole coil off of the iron easily. Neither had moved outwards though where they might have come in contact with the flywheel. Maybe the ignition wire held them in place. I may just bond them back to the iron if anyone has a suggestion as to what bonding agent to use. I did replace both coils. I found the little boots that snug up between the coil and the plug wire where the wire goes through the plate to both be not installed perfectly. Seems it’s a real tight fit going through the plate. Did it right this time. As a side note this is my first classic or antique outboard motor that I’ve had. A friend helped me (basically he did it) get it running and we replace both coils and condensers(three years ago). We did not remove the ignition plate and instead just pushed the coils into the ignition wire. I didn’t know that this was the wrong thing to do. This time of course I pulled about 4 inches of wire through the plate and then screwed the coil onto and into the wire properly.

Replaced both condensers although both seemed to check OK with a VOM meter. Both showed a very brief short circuit (.1seconds?) when resistance was measured going to open circuit almost instantly. I marked and dated them as I believe they were new from NAPA about 3 years ago.

I grounded the ignition plate to the block with the same type of wire that is used in the over rev protection circuit allowing of course for the movement the plate makes in operation.

Took it out on Lake Lanier launching at Van Pugh and ran it on Tuesday in 50°F 23mph wind with a light drizzle. No trailers in the parking lot. I was the only boat that I saw operating, guess everyone else has good sense. I know you guys understand.

It ran GREAT!

(Just to refresh, it was running terrible and I believe one cylinder was dropping out below 1400 rpm or so at first and then probably not running at all and had a very, very poor idle. Top speed was 15mph with constant violent motor jerking. I usually get about 30mph.)

It is hard to put into words how much I appreciate everyone’s input. (and further input, if you like)

Thanks.

Dan Nelson

[vintin]

I’m back in the market for some ignition wire. O’reilly’s locally is saying they don’t carry it. Looking for recommendations. I’m working on a 1969 25hp Johnson.

[frankr]

Yeah, lots of auto parts places no longer carry it because cars haven’t used it for ages. Try a parts place in a rural area. Think trucks and tractors. Also think lawn mower shops and (duh) boat repair shops.

[nj-boatbuilder57]

I just buy it from eBay. 7mm, stranded, reasonable price…

https://www.ebay.com/itm/7mm-Copper-Cor … :rk:3:pf:0

[PugetSoundBoater]

quote Jerry Ahrens:

I assume you are working on an OMC ? Just clean everything up and go with it. The mag grounds through the bushing where it pivots on the powerhead.

I have wondered the same thing as VinTin about the ground on a mag plate. it calls for some grease on the bushings ,have used triple guard and thinned it out a bit with LPS. and it worked fine.I think i should have used Lithium grease? Evidently the grease doesn’t insulate well enough to block the grounding?
I don’t mean to or intend to highjack this topic, but since this was brought up.. 😀 EDIT

"Some people want to know how a watch works, others just want to know what time it is"
Robbie Robertson

[vintin]

I was wrong about O’reilly’s not carrying the copper core wire. I just spoke with a local manager and they will have it in by 6pm this evening. It was the hired counter help that said yesterday that they don’t carry it any longer. $.79 per ft.

[crosbyman]

rubbing… just in case I added some protection on my 6r72

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[crosbyman]

quote FrankR:

Yeah, lots of auto parts places no longer carry it because cars haven’t used it for ages. Try a parts place in a rural area. Think trucks and tractors. Also think lawn mower shops and (duh) boat repair shops.

my local motorbike shop keeps it ….bikers don’t care about RF noise in the A.M. band but then again not to many AM band s around anymore

no gifts here … wire is about $2 ++

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