Sierra Coil 18-5181 OMC

[mercuryman]

I just installed 2 Sierra coils on my 1964 Lightwin and had two problems. There are screws not pins to push the wire on. This is a pain on LT hard to remove the mag. and get the wires free. Got them installed and flywheel hit coil laminates and I could not adjust to clear. Rather than grind or file the laminates I pushed out lams and used lams off the old coils. It worked out great , Sierra coils don’t use the strap to hold coil in place so its easy to do. On the positive side the new coils fired on my Merc O Tronic at less than the 1.6 amps required and motor runs fine. What I will go through to save a few bucks.

1 user thanked author for this post.

Fastwin18

[George Emmanuel]

Birny,

Somtimes you just have to outwit the merchandise! My first experience with replacing coils came many years ago when I got a Mighty Mite. The coil was dead. So I went to NAPA and found a small engine coil that was a small enough size to fit under the flywheel, but the core opening in the new coil was larger than the original. All I did was pad the opening with thin cardboard and voila!—I had spark. That led me to experiment with other coil replacements that I’ve written about. It’s when you’ve tried everything and you’re at your wits end that you take bold steps to experiment. Good job on your part!

[Mumbles]

Out of curiosity, were the Sierra laminations riveted together or stamped together? There’s more than one manufacturer of the coils over in China and you may have got lucky and found a set which didn’t have the fitment problems I went thru on a ’59 JW. I like the screw on terminal as the German Prufrex coils have this and it helps to hold the hi tension lead on.

Someone else had mentioned that the coils had a hot fire so maybe swapping them onto the old laminations will become the accepted way of installing them.

viewtopic.php?f=2&t=9075&hilit=sierra+coils

[mercuryman]

Looks like the are stamped.

[Ed Juratic]

I have a Neptune 1.5 hp. trying to find the year. It’s marked, OB 100  3/5 and on the crankcase 0-B-100-1.  Would like to replace the mag. coil, condenser and points.
Thanks.

Ed J

Phone;    440-942-3551

E-Mail; ejuratic@sbcglobal.net

[Mumbles]

The Neptune OB series of motors were produced from 1930 to 1937 but I can’t find a listing for an OB-100 or for any 1.5 horse motors.  Can you post a photo of the model number which was usually stamped on the rope sheave?

 

[billw]

I kind of like the Sierra coils because it forces me to do the right thing and put in new spark plug wires. I cut the new wire, screw it into the coil and then install the coil and wire on the mag plate. The other good thing is that they come with a new grommet. Some of the really cheap ones don’t. I do wish the primary wires weren’t so long, though.

Long live American manufacturing!

• This reply was modified 3 years, 4 months ago by billw.

[seakaye12]

This is a 2016 Thread. The Sierra products sold today may or may not have similar issues.

[billw]

Wow, how did that happen?

Long live American manufacturing!

[Author]

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