Friend has a 1970s or more likely early 80s Saxon pedestrian flail mower with a Robin EY40B pull start engine fitted with the separate coil and KTR unit.
The interlock circuitry which are supposed to prevent the engine starting when it is in gear and the clutch is engaged is long gone but the switches on the gearbox and clutch remain. Both the switches are push to make, the clutch switch makes on clutch engagement, the gearbox switch makes on reverse gear selection only. As far as I can work out, they were originally wired in series as that's what the cable remnants seem to determine.
I assume that the gearbox is for drive wheels -- is the clutch for the flail or for the wheels?
I don't know what the motor is, but I assume that if it's pull start it's got a magneto ignition. With that simple of a motor, I don't see how you can differentiate between "not start" and "not run". If the gearbox is for the wheels and the clutch is for the flail, then having the motor _stop_ (and not just refuse to start) any time you try to put it in reverse with the flail engaged is a good thing.
If it sounds like all my assumptions are correct, then my last assumption is that shorting out the points will kill the engine long before the magneto overheats, and the two switches should be in series, wired to short out the points.
What _I_ would do is go to my friendly local lawn mower supply place (NOT Sears or the hardware store -- I mean Ed's Mower Shop or Clarke's Lawn and Garden, etc.), and ask the folks at the parts counter what they think the wiring should be. Then I'd ask if they have a replacement harness (they won't), then I'd buy a set of points (because it's the nice thing to do, and because if you've got it opened up enough to get to the points, you may as well put new ones in).
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My liberal friends think I'm a conservative kook.
My conservative friends think I'm a liberal kook.
Why am I not happy that they have found common ground?
Tim Wescott, Communications, Control, Circuits & Software
http://www.wescottdesign.com
Thanks for your help. The following seems to be the solution:
From my reading of the thread and a little thought I suspect the
Reply from Robin:
That would be a logical assumption and quite possibly the answer, but the layout of the belts and clutch levers doesn't lend itself to this being the logical layout: There are two hand levers for the two clutches (calling it a clutch is glorifying it, it's just a belt tensioner arrangement), one for the gearbox drive, and one for the flail drive. The clutch lever on the left handlebar is set up to operate the left belt / clutch arrangement which operates the gearbox drive, and the clutch lever on the right handlebar is set up to operate the right belt / clutch arrangement which operates the flail drive. A simple swapping of the lever control cables will give the 'no reverse with flails engaged' scenario detailed below - and as I said above, quite possible the answer - but the controls / cables / belts layout doesn't lend itself to this and would explain why the previous owner(s) had installed it this way.
Of the two clutch levers, only one has the cut out switch facility.
Many thanks for the AFL bod who came up with this probable solution. When back at work on Monday I will see if the cables will fit the other way around.
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