Briggs Mod 23 weak spark

Tom RS

Member
I have a Briggs 23FBC on a Shaw R8 tractor that has very weak spark.
Had no spark at first so I took the flywheel off and found the ground wire for the coil off. Fixed and cleaned up the coil connections and have spark now but I can only get it to jump a 32nd gap.
The coil ohms is about 0.7.
Any suggestions?
 
If you don't want to mess with points, electronic coils are available for most of the Briggs engines.
I have used them for several years and had good results, seems as if they start better.
 
Is there a kit that would work for this Model?
I believe it dates back to the late 40s.
Do you know of anyone who has parts for this model if I want to stay with the present system?
Thanks for the reply.
 
Touch the magnets with a flat blade screwdriver to see if they have strong magnetism. I have a 23AB for sale. It was rebuilt 3 years ago. Hal
 
Harvey.
Maybe I am confused but I think this engine uses magneto ignition and therefore there are no points. If I am right, then he has little choice but to stick with what is there. Good magnets are essential. They must be strong in magnetic power or they will not induce electrical current into the magneto coil.
 
You could google antique Briggs-Stratton engine parts,
Give Bob Weaver a call at Weaver's Equipment.
He is a good ol' boy and easy to deal with.
Address:
4809 St. Rt. 61 South
Shelby, Ohio 44875
419-342-7033
I don't think he has a computor.
 
The B&S Model 23 has a magneto and has pionts, and this engine will not easily convert to electronic mag or the points eliminator, it could be the points & condenser or the coil remember the magneto is 60+ yrs old, and fi I remember they didn't have the best coils.
GB in MN
 
I have points on my Mod 23AB. They're mounted externally on the engine block covered with a metal cover. My 14hp B&S on my Wards tractor has the same thing. Hal
a160088.jpg
 
Well OK then. I stand corrected. I was not aware that some engines
used points with a magneto. It's always a good day when you learn
something new to you. LOL
 
If you had to remove flywheel to get to coil then you have the magna-matic ign system,goto link below & read,then check rotor timing as per text(move mouse pointer over text & click left mouse button to enlarge)after that try cleaning points then check for spark,if spark still weak try replacing condenser,if same weak/bad you will get little/no spark,if spark still weak after replacing condenser I would suspect a weak/bad coil or weak magnet in rotor,if you search on ebay for briggs coil these coils show up there from time to time,also the condenser.

Another common problem on these old eng is plug lead dries out & develops cracks/carbon tracks in insulation where lead passes thru hole in flywheel backplate or where wire lays against block after it leaves backplate & plug voltage shorts to backplate/block giving little/no spark to plug,check plug lead under a bright light/sun light.

Most/all magnetron(pointless) conversion kits won't work with this eng as most/all of the old number series eng(5-23)had reverse polarity on flywheel magnets compared to newer eng,in addition orig coil MUST be in good working condition,if you
have a weak/bad coil conversion won't work/cure your problem if you find one that will work on eng.
timing
 
If you have a starter/generator with a battery you can use an auto type coil. Disconnect the old coil wire at the points then run battery voltage to an ignition switch and from there to your auto coil from the coil to your points. Hal
Set the points at .020".
 
Assuming that El Toro is correct about the conversion he suggested, you cannot use just any auto coil. You must specify a coil that is designed to run on 12 volts. Many auto coils run on 8 volts because there is an external resistor in series with them that looks after the other 4 volts.

If you install an 8 volt coil with no resistor, you will burn it up as well as the points in no time flat.

Go to NAPA and tell them to look in their catalog for Outdoor Power Equipment for the coil used on Kohler K Series engines. That one is a true 12 volt coil and you can install it without any worries.
 
I would be surprised if his Shaw engine has a starter / gen but if it does then converting to battery ignition is a no brainer, I've done this conversion to a number of old cast iron B&S and they all started better and ran better the coil that works is a Wells LU800 its a 12 volt coil. And if the engine has no starter / gen and you can't find a good original coil I'd convert to battery ignition using a small 12 volt battery, you would need to charge the battery after use but would make an old reliable engine good again.
GB in MN
 
I did the same thing on my Troy Bilt tiller. I put a 10hp B&S engine on it in 2006. I just use a battery for starting usually will last to the Fall. Hal
PS: The picture was taken in 2006 before I installed the battery several years ago.
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I took a few pictures of the tiller with the battery. I just touch the green cable on the battery's neg post for making a start. I use a bungie cord to secure the battery. I gave $100.00 for the tiller in 2005. It needed tines and new seals under the tine holder. I bought the 10hp engine from the smallenginewarehouse. Hal
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a160262.jpg

a160263.jpg
 
There is writing on the side of that coil that is not easy to see. However, it appears to say

12 volts with external resistor


If that is what it says, then that is not the correct coil for this application. You want a true 12 volt coil that does not require an external resistor.
 
It will work with a ballast resistor too. Even boats have a ballast resistor that have inboard engines. Hal
 
We are all on here trying to help others and it is important that any advice given is accurate.

El Toro seems adamant about the NAPA coil IC14SB but in order to settle the controversy, I telephoned a NAPA dealer. He has that coil in stock and he confirmed that an EXTERNAL ballast resistor must be used with that coil.

He then checked all of the other coil models that NAPA offers and told me that ALL of them require the external resistor. The only coil available to him that has an INTERNAL resistor is the one listed for the Kohler K Series engines and he sells it for $35.36.

So it really does not matter whether the IC14SB coil works in watercraft applications because we are discussing which coil will work on an engine in a tractor that does not have any sort of ballast resistor located in its wiring. I don't think that El Toro wants anyone to buy a coil that will burn out quickly and that is exactly what will happen with the IC14SB NAPA coil UNLESS you also buy a ballast resistor and wire it in series with that coil.

If anyone is still unsure, then just telephone your local NAPA dealer and get them to read what is written on the side of the IC14SB coil.
 
I just called my local Napa dealer and he said their coil IC14 does not require a ballast resistor. Hal
PS: Here's their phone number. Cost is $35.00

410-272-7110
 
OK.... I called that store and he went and pulled that coil from his inventory and opened the box. According to him, that coil does not have the writing on it that the on-line NAPA photo displays. He explained that away by saying that NAPA likely used a generic photo of a coil and that the same photo was likely used for many of the coil listings. That seems to be reasonable to me.

What is puzzling though is that the NAPA store I called this AM was positive that an external ballast resistor was needed but your guy says that the IC14SB does not need one.

So.... it is now in the hands of those who need a coil for their tractor to make 100 percent sure about the coil they are buying before they leave the store. I have done my part in alerting people that some coils need the external resistor and some do not.
 
As I posted the Wells LU800 coil is a true 12 volt coil and it only cost $12 -$14.00.
GB in MN
 

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