Converting A Four Stroke Glow To CDI Ignition

Recent comments by SrTelemaster150 outlining the virtues of using CDI ignitions on glow four stroke engines are intriguing.  His arguments are that no nitro is needed, oil content can be reduced and fuel economy will improve.  I'm not a stranger to mixing my own fuel and less oil means less cost and effort needed with clean up. 

At play as well for me is easy starting as I've a distaste for starting the large glow 4 strokes,

A few years ago,  I bought a NIB YS-120 intending to use it on the an Akrobat II.  After a few weeks effort trying to break it in on the bench, I gave up on it mostly due to discovering that the engine required high nitro content to run reliable, which I deemed beyond reasonable for a sport flyer.

Converting this engine to CDI will be an interesting effort and one within my scope.


Needed will be a CDI setup for a 1/4 x 32 plug but they are readily available and of course can be used for many applications so the small investment would not be lost if the project doesn't pan out.  And... I've a Saito 182 twin that would benefit from a similar effort and possibly the Saito 125 that is currently in use.

I've ordered a CDI ignition to try to make the YS-120 operable... nothing ventured... nothing gained, eh.

Update: The timing ring has been machined and awaits a magnet.  The ignition has been shipped so will be here soon and the YS is mounted on the engine test bed and a suitable prop chosen.  So... my finger is on the trigger for testing.  The only thing not done so far is to mix FAI fuel but that will be done after first getting the engine to run properly with a regular 15% nitro mix in part to make a comparison between the two fuels.





Update Early April

After installing the ignition, the motor started without major effort but ran poorly
. To avoid leaning on top end, the HS mixture has to be set at a point that at mid range the mixture is so rich the engine will barely run and in fact won't spool up.  Leaning will allow spooling up but then be too lean on top end.  The engine suffered a couple of back fires and quick halts and may be damaged as it will no longer even start.

I'm throwing the towel in on it.  It needs looked at by an expert and I'm not sure it is worth the trouble.  My conclusion remains as previous and is in line with those of others, it is too problematic for a sport engine.

I'll likely install the ignition on my Saito 1.25.