What engine is this?
- Thread starter daves66nova
- Start date
Looks like some type of Briggs engine, although I'm not super knowledgeable on Horizontal shaft engines, if it's a Briggs I'd think there's be a stamping somewhere on it with the model number and date code.
It's a 70's era Briggs. The recoil mechanism confirms..
Don't order a coil ( I doubt that's your problem) until you pop the flywheel off to lightly clean the points with an emory cloth. Then pass a dollar bill or a piece of paper between the contacts to clean. I would bet that will solve your problem. Verify the point gap is at .020 and If the flywheel key is damaged, replace it before installing the flywheel.
Last edited:
Oh ok. I didn't know it had a point. Thanks!
Yes that's a Briggs with a points system. You can tell for sure by looking for a small wire from the coil leading to under the flywheel. As noted, when sitting unused, the points can get rusty, wet, or oil covered then it will not spark. Electronic coil upgrades were available.
The engine model number will be stamped on one of the sheet metal covers, either the main flywheel cover or the side cover.
The engine model number will be stamped on one of the sheet metal covers, either the main flywheel cover or the side cover.
Briggs, likely a 3 hp (or under) because of the Vacu-Jet carburetor. Yes, it has points. The coils on these points-type systems almost never fail. Use a standard business card to set the coil gap. Replace the points and condenser, they are cheap. The point gap is 0.020".
The flywheel will have to come off. The starter clutch will have to come off first, it uses standard threads (lefty loosey, righty tighty). Don't hammer on the end of the crankshaft to get the flywheel off, use a knocker https://www.amazon.com/-/he/750-191/dp/B09H7MW6GS
Take a close look at the aluminum flywheel key after you get the flywheel off. The engine will lose spark if it is even slightly sheared.
The flywheel will have to come off. The starter clutch will have to come off first, it uses standard threads (lefty loosey, righty tighty). Don't hammer on the end of the crankshaft to get the flywheel off, use a knocker https://www.amazon.com/-/he/750-191/dp/B09H7MW6GS
Take a close look at the aluminum flywheel key after you get the flywheel off. The engine will lose spark if it is even slightly sheared.
Last edited:
A damaged flywheel key itself will never kill the spark , as long as the crankshaft is able to turn with the flywheel which it would probably do even with a sheared key.. A sheared key will affect the timing of the spark and create a no start condition.
Negative. A B&S engine with points will lose spark if the flywheel key is sheared (in some cases, even partially sheared). The electronic Magnetron ignition will not lose spark.
Might check the condenser too. I've found a few bad ones over the years, but not often.
The condenser on this engine has one of the two points built on top of the condenser, so the points and condenser only come as a kit, part number 294928.
https://www.amazon.com/Briggs-Stratton-294628-Ignition-Horizontal/dp/B0038U3LBO
Sorry not drinking the kool aid. Explain how that could be. I had sheared keys on old Briggs engines and had a spark.
The points have to be synchronized to open just as the magnet passes the coil. If out of sync, the energy that the magnet places into the coil will dissipate before the points open. The opening of the points is controlled by a bump on the crankshaft thus it has to be synchronized to the flywheel with the key.
Back in the day, when these small engines were first designed, B&S specifically designed the ignition system to lose spark if something was hit hard enough to shear the flywheel key so that an average homeowner would have to take their mower to the shop to get it fixed. They did this for safety. They wanted a professional to look at the mower to determine if it was damaged in such a way as to be dangerous.
mk378 beat me to the scientific explanation. If your old engine still had spark with a sheared flywheel key, it had electronic ignition, not points.
BTW, a properly functioning ignition system that still has points will give you a stronger/fatter spark at a lower RPM than the newer engines with electronic ignition. This was advantageous during the leaded gas era. B&S came out with the Magnetron electronic ignition in 1981, about the time that leaded gas was being phased-out. They sold points ignition engines for a short while longer, offering the manufacturers the Magnetron ignition as an "upgrade" (mostly for marketing purposes).
Last edited:
If it could run without a flywheel key, it wouldn't have a flywheel key. They didn't spend money on a single part that isn't essential for it to work.
The reason the key is aluminum not steel is so the momentum of the flywheel won't break the crankshaft when the mower blade hits something solid. Which isn't an issue on a belt driven machine but they don't want to have to source two kinds of keys.
The reason the key is aluminum not steel is so the momentum of the flywheel won't break the crankshaft when the mower blade hits something solid. Which isn't an issue on a belt driven machine but they don't want to have to source two kinds of keys.
You have to take the flywheel off to work on the points. The coil can basically stay attached for the life of the engine. Under the flywheel, there's an aluminum can around the crankshaft that holds the points.
I still can't see from any of your pictures whether or not there is a wire leading under the flywheel. If there is not, it would be electronic ignition not points.
I still can't see from any of your pictures whether or not there is a wire leading under the flywheel. If there is not, it would be electronic ignition not points.
I'll check later today. If it's points, would this work to make it electronic? https://www.amazon.com/Raogoodcx-Re...prefix=electronic+coil+briggs,aps,269&sr=8-20
Doesn't look like that would work, it says it's for 10-13 HP L-head, and others have said you probably have a 3 HP or smaller. I'm thinking that one is designed for a larger flywheel, so even if the mounting holes are the same, you won't be able to set the air gap correctly because the curvature won't match. Is there a wire from the coil going under the flywheel? If not, maybe it was already converted at some point. A better picture of the coil (specifically, the armature side that faces the flywheel) would help. An electronic ignition would have a small round pickup next to the large coil that has the spark wire coming out of it.
So i look for Briggs 5hp electronic coil?
Similar threads
