Hi There Gentlemen,
I have a Condor mower, which, a few weeks ago stopped, as I was tackling a particularly tough patch of scrub on a very hot day (in June!) No spark. The spare for the 8 Hp Kohler single cylinder petrol 4 stroke was over 100 pounds and not available immediately. My problems with it are more fitted to this forum, as I am sure many of you have had similar problems with model engines.
It has a permanent magnet going round in the flywheel, which passes by an Electronic module under a recoil starter cover and another engine cover. Not too easy to get off. As the module was dead as mutton I carefully dismantled it - with a saw and angle grinder, as it was very hard plastic. I did not see any electronics but the laminated former of soft iron and the inside of the coil were retained. This formed an E shape and obviously generated a spark when the flywheel magnet passed it.
First of all I tried to attach a reed magnetic switch to the coil bracket, using a normal condenser coil and 12v battery, for which there is ample room. This worked to start with but did not last long as the contacts started to become intermittent and then fused together. Next I wound a coil round the former to generate a pulse to feed into the 12v car coil, but the spark was miniscule. This is all documented in the Farmers Forum, but the subject has dried up there and this forum is probably more appropriate, (so come on you engineers!)
- using the coil which I had made, to trigger the modules I got a spark which was truly magnificent. At least half an inch. Even though the timing of the spark is from the same rotating magnet, there is something wrong as when I put it all together all I got was a sort of chuff and no inclination to run. I set the plug gap to 25 thou to avoid the spark happening all over the place.
The engine, being designed to run with this fixed unit is not even equipped with any timing marks, there is nothing in the manual about the firing advance and I really do get the impression that they do not want people to fix their engines by connecting up General motors HEI systems! An email to the Company asking what static timing setting should be suitable has produced no response at all.
I connected an electric motor to the drive belt to motor the engine at about tick-over and marked a couple of lines on the flywheel and crankcase and, using my strobe timing light I have calculated that the nice fat spark is occurring at 14.4 degrees before TDC. The flywheel is 25 inches in circumference and the gap between TDC and the strobe position is about an inch. To me that does not seem too much out, but it must be. My Corvette starts with a static advance of about 8 degrees, but it shoots up to about 30 odd when it is revved up. The Kohler 8 Hp. is not quite in the same class, is it?
Making the coil adjustable is the next step, but it is not going to be that easy. There is not much room to put a sub-assembly in to allow this, so it I can find out what it should be, I can make a fixed bracket. I would not think that the original system had any advance and retard - at least I did not find anything that sophisticated when I took it to bits. I doubt very much if I will find anyone willing to dismantle their mower, create timing marks and find out what is the timing advance on a working model.
So my queries are as follows: Does anyone have a pretty good idea of what it might be? I understand that the earlier models did not have this electronic "coil". If anyone had one they might remember.
Thanks and regards George.