SCOTT ATWATER IGNITION COILS

[JIM MCCARTHY]

I HAVE A 1958 60 HP SCOTT ATWATER THAT HAS A BATTERY OPERATED IGNITION SYSTEM MUCH LIKE ONE WOULD FIND IN AN AUTOMOBLE OF THAT ERA. IE, POINTS CONDENSERS AND ONE COIL FOR EACH CYLINDER. IT IS NOT A MAGNETO OPERATED SYSTEM. ONE OF THE COILS IS BAD AND WILL HAVE TO BE REPLACED, BUT THE ODDS OF FINDING A GOOD COIL FOR THIS OLD ENGINE ARE PRETTY GRIM. I WOULD LIKE TO KNOW IF IT IS POSSIBLE TO REPLACE THE BAD COIL WITH ONE FROM ANOTHER ENGINE AND IF SO, WHAT DO I NEED TO KNOW TO DO IT. THE LAMINATIONS ON MY CURRENT COIL ARE STILL USEABLE AND COULD BE USED WITH ANOTHER COIL WHICH HAS THE SAME SIZE HOLE, BUT I DON'T KNOW HOW TO CHOSE ANOTHER COIL. I DON'T KNOW OF ANY OTHER OUTBOARDS THAT USED THIS STYLE OF IGNITION, NOR DO I KNOW WHAT I MIGHT RUN INTO WITH REGARD TO RESISTANCES WATTAGES ETC, OR IF IT EVEN MATTERS.

CAN ANYONE HELP ME IN COIMING UP WITH A REPAIR OPTION FOR THIS PROBLEM?

THANK YOU,

JIM MCCARTHY

 

[flyingscott]

Join the AOMCI they will be a great source of info and parts. Where are you located?

 

[JIM MCCARTHY]

I TRIED AOMCI, BUT NO LUCK SO FAR. THE ONLY SUGGESTION I GOT WAS TO TRY A COIL FROM AN OLDER OMC ENGINE. TRIED THAT-NO LUCK.
HERE IS A PICTURE OF THE BAD COIL. IT IS A REPCO COIL, BUT I SEE NO PART NUMBER ON IT. IF I COULD COME UP WITH A PART NUMBER (OTHER THAN THE SCOTT NUMBER) MAYBE I COULD CHASE DOWN A SUBSTITUTE, BUT SO FAR I'M NOT MAKING ANY PROGRESS. I COULD TRY A COIL FROM A DIFFERENT SCOTT OUTBOARD, BUT THEY WOULD ALL BE MAGNETO COILS WHICH I THINK WOULD BE DIFFERENT COILS, IE NOT BATTERY OPERATED .
AS FAR AS WHERE I AM LOCATED, COUERDALENE IDAHO, IN NORTHERN IDAHO. ANY FURTHER HELP WOULD BE APPRECIATED.

 

[brim_buster]

https://www.repco.com.au/en/parts-service/fuel-ignition-exhaust/ignition-coils-modules/c/1862918217?q=%3Arelevance%3ApartSlot%3AIGNITION%2BCOIL%3A1862918217%2F1374563120%3ATransformer&text=#

 

[flyingscott]

Let me look at mine but I believe OMC coils work you just need to mount them. The 74-76 OMC 9.9/15 coils would probably be the best.

 

[JIM MCCARTHY]

I'LL STANDBY

 

[flyingscott]

Ok I looked at mine and the 74-76 OMC coils should work. Are you sure you do not have bad set of points or condenser?

 

[JIM MCCARTHY]

POINTS AND CONDENSER ARE FINE. THIS IS A THRE CYLINDER ENGINE AS YOU KNOW, SO WHEN I IDENTIFIED THE PROBLEM, I SIMPLY SWITCHED THE COIL THAT WAS SUSPECT TO ANOTHER CYLINDER THAT WAS GIVING ME A GOOD SPARK. IT THEN CONTINUED TO GIVE NO SPARK AND THE GOOD COIL CONTINUED TO GIVE ME A GOOD BLUE SPARK. I'M SATISFIED THAT I HAVE A BAD COIL. I HAVE ALSO REWIRED THE ENTIRE ENGINE AND WENT THROUGH THE POINTS AND CONDENSERS AT THAT TIME. THE POINTS ARE IN GOOD SHAPE, BUT I DON'T HAVE THE EQUIPMENT TO CHECK THE CONDENSERS.

IN THE MEANTIME, I GOT LUCKY AND FOUND A PART NUMBER FOR THE ORIGINAL COIL (PART # REPCO FG 3681 BY THE WAY) AND WAS ABLE TO ORDER ONE. I HAVEN'T RECEIVED IT YET, BUT ASSUMING IT IS A GOOD ONE, MY PROBLEM IS SOLVED, AT LEAST FOR THE MOMENT. KNOWING THAT I MAY NOT EVER FIND ANOTHER ONE THOUGH, I'M STILL INTERESTED IN RELACING THE ORIGINAL COILS WITH SOMETHING MORE CURRENT AND AVAILABLE. ONE OTHER POTENTIAL PROBLEM I HAVE DISCOVERED IN CONVERTING TO THE OMC COILS HOWEVER IS THE CONDENSER ISSUE. IF I REPLACE THE CURRENT REPCO COILS WITH OMC COILS, SHOULD I WORRY ABOUT THE CONDENSERS HAVING THE PROPER VALUES? I UNDERSTAND THAT COILS ARE MATCHED TO THE CONDENSERS THEY ARE USED WITH, AND IF SO, SHOULD THE CONDENSERS BE REPLACED WITH OMC CONDENSERS AT THE SAME TIME THE OMC COILS ARE PUT IN? NOT KNOWING THE VALUES OF THE CONDENSERS FOR EITHER COIL, IT SEEMS REASONABLE TO REPLACE THE CONDENSERS AS WELL, BUT I'M NOT KEEN ON THE REMOVE AND REPLACE APPROACH TO DIAGNOSING AND REPAIRING ENGINE PROBLEMS. IF THEY NEED TO BE REPLACED I WILL DO SO, BUT NOT UNLESS THEY ARE NEEDED. THEN THERE IS THE SPACE PROBLEM TO BOOT. IT'S PRETTY CROWDED AT THE BOTTOM OF THE GENERATOR AND FINDING CONDENSERS TO FIT COULD BE PROBLEMATIC.

ANY THOUGHTS?

 

[matt167]

The condensor's purpose is to prolong the life of the points. The condensor absorbs electricity to lessen the arc seen on the points. The coil fires when the field on the primary collapses. The only thing that matters is that the field collapses. coils are measured in ohms of resistance. The less ohms, the more current when the primary collapses, makes more voltage in the secondaries through induction. Most condensors are around the same value and mounting becomes the differences.

All you have to do is ohm your good coil, to see what it is on the primary side, and then get a coil that is close, which I'm sure the OMC coils are. It's points ignition, so it does not have to be exact. A coil with less ohms would burn up the points faster, and a coil with more ohms will make less spark, but within a small amount it won't matter one bit. points ignition is not that complicated