Atco 2464 Lightweight 150cc
The mower has a Villiers 599D engine. Have fitted a new electronic ignition from Villierparts, and have
had the flywheel re magnitised. But still only get a poor spark. This set does away with the points, so
no problem there.
Does anyone know if the ingition timing given in Villiers Technical Data as !8 degs Before TDC
is correct with this set up.
Why not start by asking George at Villiers Parts ? If anyone will know he should !
However some electronic conversions do need a higher rpm to produce a decent spark than a points system in good condition.
Out of interest, who did you use for the remagnetising of the flywheel?
George told me to set timing TDC with arrow on flywheel in line with the
back plate mark. Not to bother with after or before TDC
I sent the flywheel to Villierparts who sent it on to Villier Service at
Brierley Hill, and ended up dealing with them. Magnet strong on return,
the total cost £28.80
Thanks for your help
It is my understanding that when Villiers built the engines they set the timing by a before top dead centre measurement of the piston position down the bore but stamped in the arrows in relation to TDC so that future repairers could obtain the correct setting without having to remove the head ot resort to timing discs etc. So what George has told you is correct as it takes account of the specified TDC setting.
I'm not sure whether all Villiers engines have this feature but many have a little notch cut in the threaded end of the crank which corresponds with TDC so that with the engine on a level surface and that notch at 12 o'clock the piston will be at TDC.
Interesting to know about flywheel re-magnetising but I have to say that in more years of playing with small engines that I care to remember I have never experienced an ignition failure due to low flywheel magnetism - all other factors being equal. However assuming that it has been correctly magnetised it should contribute to a "spot on" ignition system - but I have heard of a few cases of incorrect polerisation after re-magnetising.
Will look for the little notch on the end of the crank.
Am just able to see the top of the piston through the plug hole,
so have been conifident of its position. Though not too sure if
I have been setting the timing on the compression or exhurst stroke.
( A friend said it may not matter with this engine )
will have to take the valve cover off to check. Will keep you posted.
As the ignition contact breaker cam runs at crank/ engine speed with a "wasted spark" on the exhaust stroke you can set the timing on either the exhaust or compression but I guess that it would be considered "good practice" to do it on compression.
Locating exact TDC is a little more scientific than poking a bit of wire through the plug hole but for this sort of engine and application is probably OK although as you have probably discovered there is a "several degree dead spot" between "going up and going down"
Finding exact TDC on this or higher performance engines can be achieved with a piston stop and 360 degree timing disc or a dial indicator.
Have taken the clutch sprocket off the crank, but no notch found.
Am now getting a spark on the TDC setting. Not yet firing up. Take your point regards
several degrees of dead spot. I have made a timing disk with a 6 1/4" card circle and a protractor
set to 18 degrees BTDC. Will play around in this area.
The tank and carb have been serviced, piston, rings, and oil seals changed. ( Camshaft ang gear
positioned mark to mark) So any time now.
Clutch sprocket - is that a kick start ratchet/clutch on the flywheel /magneto side of the engine? That's the end of the crank where the notch will be if at all. It's only a little V nick in the thread .
Now that you've made a timing disk you have the means of finding the exact TDC rather than the "by feel" near enough one. I'll send you a pm later with details.