Chris Walby Posted May 29, 2018 Share Posted May 29, 2018 Any news of finding out what the issue was.... Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted May 29, 2018 Author Share Posted May 29, 2018 Waiting for the owner to bring it to the club again, complete with test stand and substitute ignition module... Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted June 22, 2018 Author Share Posted June 22, 2018 At last, an update... The engine appeared at the club on a test stand along with a borrowed module a couple of weeks ago. Carb settings were taken back to recommended starting positions. After a few turns with the starter it burst into life and with minor adjustments was running beautifully. The original ignition module was still buried in the owner's model which had been left at home so the final test of running on it had to wait until yesterday afternoon. With the engine re-installed into the model with the original electronics, after a protracted attempt before it started to fire, the original symptoms of stuttering mid-range with what sounded like rich running preventing meaningful top end revs had returned. The borrowed module was substituted and the engine burst into glorious smooth and powerful running. So, problem proved to the ignition module but no real explanation for the single instance of running perfectly in the reverse direction. I have to admit completely forgetting to check the position of the magnet/sensor relative to TDC - perhaps I'll get a chance sometime soon... My suspicion is that the timing advance function has developed a fault - possibly due to the loose plug cap noticed on the first attempt at running the engine in the new model. Rather than it running rich, the lumpiness may have come from grossly retarded running - especially if my theory that all advance is controlled by the module from a starting position referenced by the sensor at TDC? This would explain the impossibility of improving the top end by leaning out the mixture with no apparent change from lumpy running before a sudden lean cut. Thanks all for your interest and suggestions. Edited By Martin Harris on 22/06/2018 01:35:04 Quote Link to comment Share on other sites More sharing options...
onetenor Posted June 22, 2018 Share Posted June 22, 2018 Just one question.. Were the points and condensor checked? Or the electronic version of them.? I have seen some really odd things when these were faulty including a 4 feet long arc from the coil in my right hand to the tip of my left middle finger OUCH! A new coil and the car ran like never before even from new. It was a real TGIF car. I corrected loads of faults on it. One was an out of truth flywheel found when I was cleaning the friction face. Smoother running afterwards.. The mounting face and friction face weren't parallel..The result was only half the friction plate was being gripped. What a difference. I know I've drifted off topic but it was to illustrate a point. Sorry mods. Quote Link to comment Share on other sites More sharing options...
Chris Walby Posted June 22, 2018 Share Posted June 22, 2018 Thanks for the update, will the maiden be tomorrow at the BBQ? Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted June 22, 2018 Author Share Posted June 22, 2018 Unlikely Chris - you know who the owner is...and there's going to be the small matter of getting it through the noise test as well! OT, these units have a Hall effect pick up permanently wired to a small integrated ignition unit - just a tin box with a power connection and HT lead being the only other wires emerging from what is probably an encapsulated unit (I haven't looked at prising one open) so there's nothing really to check, with the exception of the power supply wiring in the model as that was bypassed on the final check. With the vibration levels of a 45cc single, if there was an intermittent switch or wiring fault I suspect that the symptoms wouldn't be so consistent. Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted June 22, 2018 Share Posted June 22, 2018 Posted by onetenor on 22/06/2018 05:33:06: Just one question.. Were the points and condensor checked? Or the electronic version of them.? I have seen some really odd things when these were faulty including a 4 feet long arc from the coil in my right hand to the tip of my left middle finger OUCH! A new coil and the car ran like never before even from new. It was a real TGIF car. I corrected loads of faults on it. One was an out of truth flywheel found when I was cleaning the friction face. Smoother running afterwards.. The mounting face and friction face weren't parallel..The result was only half the friction plate was being gripped. What a difference. I know I've drifted off topic but it was to illustrate a point. Sorry mods. John, the equivalent of points on a modern electronic ignition of this type is an electronic device called a 'hall sensor' which is triggered by a magnet in the prop driver passing under it. The electronic module is a self contained unit that amplifies the trigger signal and generates the HT voltage. It uses such small currents that the old condensor is now redundant, though if one wanted to be picky no doubt there are solid state condensors (capacitors) serving other purposes within the module. Martin's friend effectively swapped out the points and condensor (or modern equivalent) when he ran the engine on a stand with a borrowed module. As with much modern gear there is little user adjustment to be done by the average Joe, parts just have to be replaced. Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted June 22, 2018 Share Posted June 22, 2018 Martin was replying too even as I typed Quote Link to comment Share on other sites More sharing options...
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