Caps for John

[jeff-register]

John,

Looked up some data on caps for magnetos for you. Look up Digiking on the web, next go to Vishay 1832 caps. then go toMKP 1939422134HQ series. They are the best I found a few years ago, cost $4.33 each. & pick  your required micro farad required. These caps will live in a magneto placement & some will fit in the cap shell. If anyone has a newer/better cap please help John or anyone else. Thanks for asking..

P.S. don’t forget the H.Q. at the end. “High Quality” for magnetos  & look at data sheet for details  😉

 

[crosbyman]

OK i’ll  be honest…

I have rebuilt caps but never actually tried them yet…

based on M.Mohat’s  rebuild articles on rebuilding and TESTING caps  where voltages  on the coils approaches 250-300 v  DC  during the  EMF  kickback   when points open up..

I have used these  inexpensive ones which can be  fitted inside old cap cans and  covered up with epoxy or simpply installed bare.

Anybody tried them in a working magneto  ?

 

 

Joining AOMCI has priviledges 🙂

[joecb]

Go with Jeff’s recommendation on the Vishay HQ caps I and others have used them and they do the job.  The .22mf size will meet most all of your needs.

Joe B

[olcah]

Well FWIW my experience with Digikey capacitors has not been that good.  In short when installed bare they did not fit on the mag plate well.  I used Digikey part BC2609-ND , Vishay MKP1839-HQ 220 n +-5%, 850V.  I suspect the capacitor failed when running because I had bent the light wire excessively.  Before the motor ran very well but skipped when the wire eventually broke.   Motor is a 1956 Johnson 15 HP.

Had another failure with a 1956 Evinrude 15 HP.  In short I was messing with the motor using starting fluid and got a large backfire.  Bent even the linkage that rotates the mag plate.  The cap was hit by the flywheel and torn away.  I think the points fired when the capacitor was hit.  I assume capacitor had shifted position as the motor had previously run ok.

Maybe someone can suggest an improvement in how I mounted the capacitor?  The motors did run well with these caps.

Here is a photo of the caps installed on the mag plate.   Ignore the 1st attachment.  For some reason I can not edit it out

[joecb]

Because the leads are solid copper wire they will fracture from vibration. The caps must be secured to prevent vibration. Either pot them in the old metal cans of improvise a strap clamp to hold them secure.  For example, if the old caps were held in a metal circular clamp, you can wrap the new one in several turns of tape to fit the old clamp.

The cap just hanging out on the air supported only by the copper lead wires will fail.

Joe B

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olcah

[crosbyman]

https://wrcoutboards.org/wp-content/uploads/2020/04/Part4_Repairing_Broken_Condensers.pdf

Joining AOMCI has priviledges 🙂

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olcah

[Buccaneer]

OMC Universal mag capacitors are readily available, but the
Sierra ones I got a while back tested at .27 mfd’s new.
Not sure about OMC labeled condensers, but doubt they’re
up to specs now days either.
The axial caps aren’t a good fit for installing in the OMC
Universal Magneto condenser cans.
I purchased a couple of those little ceramic ones a couple of years
ago, but haven’t used them yet.
They sound like “more work”, but they’d probably find in
the old condenser can. Anyone use the Ceramic ones yet?

Prepare to be boarded!

[jeff-register]

I too have bought the Vishay caps but never used yet. I’m going by the factory rep’s advice. true these caps were speced out to handle magneto voltages & not so much the envirement of an outboard. I’m sure potting compound would solve this issue. It is available at Digiking as well. Thank you everyone for your input!P.S. Olcah, I can see some of the issues in your install, The device needs to be mounted & the leads need to be insulated. In the past I have used oversized wire insulation as a covering around bare leads in radio work. Keep them from moving with a dab  of super corona dope or any glue. I do know the caps are made a little big but are reliable replacement. Digiking is a distributer not a manufacturer. Hope this helps.

PS Bil,l Looked up the X7R cap at Digikey tonight, no longer availble, too bad.

This is how we solve problems collectivily1

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olcah

[Finn Freeman]

I would like to put my word in for the Ceramic Capacitors. I got my first two at Constantine from Jay Miller, and since then have bought a few more. They run great in my ’62 Evinrude, and I plan to put them in everything else that needs condensers. It takes a little bit of soldering skill to get them together but well worth it.

https://youtu.be/oIAvoFX4-Ko

https://www.digikey.com/en/products/detail/murata-electronics/krm55tr73a224mh01k/4905676

 

[jeff-register]

Thank you Finn! I was wondering if there was a new builder, it’s called Murata & Digikey has them!

Jeff

[Author]

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