Hi again all, I have another question pertaining to the B & S engines. On a 3hp motor that has the pulsa jet carby and has the points and condensor under the flywheel. Can the points system be done away with altogether and a later model coil with the inbuilt module be fitted. The reason being the small wire that runs from the original coil to the points system has come away from the coil and it looks too intricate to reattach it, so I was wondering if I could replace it with a later model coil thereby bypassing the points and condenser.
Hi Jack, I'm interested to know how you can use the original coil, I have always just cut the coil wire to the points off, leave the points/condensor inside and fit the later coil and job done. If you used the original coil wouldn't that require fitting an electronic ignition module?
Hi Jack, I'm interested to know how you can use the original coil, I have always just cut the coil wire to the points off, leave the points/condensor inside and fit the later coil and job done.
Hi Norm, Yes, the Magnetron simply clipped to the original coil. Later engines had an integrated design.
Flywheel magnetos operate on the same principles - whether the coil accompanied a set of points & condensor, an electronic module with original coil, or a purpose-built coil/module assembly.
As you have found NormK it is just easier and more cost effective to use the newer electronic coils when available. There is usually plenty donors around from blown engines.
Originally Posted by NormK
Hi Jack, I'm interested to know how you can use the original coil, I have always just cut the coil wire to the points off, leave the points/condensor inside and fit the later coil and job done. If you used the original coil wouldn't that require fitting an electronic ignition module?
Yes. If you ever work on Kawasaki engines you will find many have an external ignitor setup.
For us here in the US we have an universal ignitor module available to use which allows us to convert many point systems over to electronic while still using the older coils. Using an universal module allows us to repair both positive and negative grounds systems. They sold under the names Atom and Nova II or you can the Kawasaki ignitor if your engine is a negative ground type; it just that the Kawasaki version is fairly expensive here. I do the older cast iron block Briggs were positive ground. These allows repair older chainsaws here that electronic ignition are not available for. Most modern engine are negative ground but older engine can be either way.
The OP here wasn't able to use this system as the trigger wire of the coil was broken off at the coil.
With addition of the self contained electronic triggers allows the manufactures to start using variable spark advance designs which when they fail can give to some pretty strange ignition problems. Anything from backfiring through the carburetor to shooting flames out of the exhaust. I have personal seen both.
I am just chiming in with a question on these ignition conversion modules. I purchased one recently for a Kirby-Lauson VK-30. I have not been able to get it to work. Every now and then the engine fires, but it appears to be mis-firing. I have double-checked the timing and the armature is where it should be.
The thing that has me puzzled is how do you know if an engine is positive or negative ground?
I assumed these engines would be negative ground, as the earth wire from the coil is covered in blue plastic. However to confuse things, the wire to the stop switch is white with a red terminal, which could suggest positive earth.
So can anybody please tell me if these Kirby-Lauson engines were positive or negative earth?
I have good spark on test, but could the timing be reversed if I've got the positive or negative the wrong way around? I am tempted to try it the other way, but thought I should ask first in case I damage the module.