BairleaFarm 339 #1 Posted September 2, 2008 Whats its do? Share this post Link to post Share on other sites
linen beige 14 #2 Posted September 2, 2008 Whats its do? When the points open the condenser "soaks up" the juice that's left in the primary circuit and prevents it from jumping the point gap (electricity follows the path of least resistance. Closed points offer less resistance than the condenser, which is a capacitor, and the condenser offers less resistance than an open point gap.) That all but instantaneous switching of circuits from primary to secondary windings in the coil allows it to give a high voltage for spark. A bad condenser, or a poorly connected one, can make an engine backfire, start hard, idle rough, cut out, etc, just as bad fuel or water in the fuel will. Share this post Link to post Share on other sites
oldandred 15 #3 Posted September 2, 2008 Jim you forgot it can get hot and quit at any time :banghead: Share this post Link to post Share on other sites
BairleaFarm 339 #4 Posted September 2, 2008 So it lets just enough :juice" through to make the points work when closed but not enough to make the jump with the points are open? Share this post Link to post Share on other sites
linen beige 14 #5 Posted September 3, 2008 So it lets just enough :juice" through to make the points work when closed but not enough to make the jump with the points are open? Not exactly, but my reference to the condenser being a capacitor may have lead you to think of a capacitor used as a filter to flatten the wave form of current to pure D.C. The rotation of the magnets in the flywheel passing by the stator (creating A.C.) causes a build up of magnetic energy in the primary circuit of the coil. When the points open the breaking down of this magnetic field causes the secondary windings in the coil to produce energy. This energy is enough to provide a hot spark across the gap of the spark plug. The breaking down of that magnetic field also produces enough energy in the primary circuit to jump the gap in the points. The condenser/capacitor is sort of a battery that can take or give off a full charge in an instant, it absorbs the energy in the primary circuit and prevents it from jumping across the point gap. When the points are open there is no current going into the condenser since it offers more resistance than the closed points. When the points open the resistance caused in that circuit downstream of the point gap is greater than the resistance of the condenser, so, electricity now flows into the condenser and is absorbed out of the circuit. The charge that the condenser takes on while the points are open flows out of the condenser to ground. As Old and Red said, they can get hot and quit at any time. If the point gap is too far out of spec.s, or the ground connection for the condenser is not good, then the condenser will soak up more juice than it can discharge to ground and will overheat and stop working. Share this post Link to post Share on other sites
papa 0 #6 Posted September 9, 2008 Speaking of condensers, I needed to replace the condenser on my K91 so instead of ordering one, I stopped by my local small engine repair shop. He promptly layed a new one on the counter and rung-up $12.59 on a register (excluding tax). Needless to say, I bought a replacement elsewhere. That's the thanks I get when I try to support local business's. Share this post Link to post Share on other sites
linen beige 14 #7 Posted September 10, 2008 Speaking of condensers, I needed to replace the condenser on my K91 so instead of ordering one, I stopped by my local small engine repair shop. He promptly layed a new one on the counter and rung-up $12.59 on a register (excluding tax). Needless to say, I bought a replacement elsewhere. That's the thanks I get when I try to support local business's. I've seen them for less than $3 online! And make sure you get the right one! Some of them had a wire lead, some didn't. And I've re-read my last post a dozen times knowing something was wrong, but I just now spotted it. I started the 3rd paragraph saying that when the points are open there is no current going to the condensor. :imstupid: I meant to say that when the points a CLOSED there is no current going to the condenser. Now that sentence might make sense! :USA: Share this post Link to post Share on other sites
WheelHorse_of_course 99 #8 Posted September 10, 2008 Just to clarify the above. The condensor acts as a spark suppressor. One of the symptoms you can get if it is bad is the points get pitted unusually quickly due to excess sparking. A good analogy is water hammer. When the points open there is a sudden stopping of current in the primary of the coil. The current wants to keep flowing (this inertia-like property is called inductance) and a spark occurs. This is analogous t the bang you get when you turn off a water tap suddenly. What the condensoer does is act like a spring or shock absorber. It absorbs enough current to allow the current to stop without a spark. Just like a water hammer preventer uses a tank full of air to absorb the shock of the water to prevent the bang. I hope this helps :banghead: Share this post Link to post Share on other sites
oldandred 15 #9 Posted September 10, 2008 Speaking of condensers, I needed to replace the condenser on my K91 so instead of ordering one, I stopped by my local small engine repair shop. He promptly layed a new one on the counter and rung-up $12.59 on a register (excluding tax). Needless to say, I bought a replacement elsewhere. That's the thanks I get when I try to support local business's. PAPA youre right been there done that :banghead: Share this post Link to post Share on other sites
