Les Turrall 2 Posted May 19, 2009 Share Posted May 19, 2009 A Clubmate has an ASP 52 two Stroke which has started to eat glow plugs at an alarming rate,five being consumed within a couple of days. I have dismantled the engine and carb completely and have observed nothing out of the ordinary. The engine was reassembled and started easily. After tuning the engine was run at fairly high RPM on the test rig spinning an 11x6 APS prop. After acouple of minutes the engine faltered and stopped. Blown plug again. OS no8. Can anyone throw some light on this problem cos at £5 per plug it's going to soon be cheaper to replace the engine!! He doesn't like electric so it's no use trying to convince him to convert ! Any suggestions would be welcome. Regards. Les Turrall. Quote Link to comment Share on other sites More sharing options...
ken anderson. Posted May 19, 2009 Share Posted May 19, 2009 hello les-the prob could be putting to many amp's through when it's been started off the remote pack gear--or running it too lean or last some old bit of plug or debris inside somewhere--don't buy £5.00 plug's...try some cheaper one's even an idle bar plug.....there was a thread on here somewhere by jim carss--he had found a way to put the coil back into plug's(joke 's ).....i would try a turn back from lean----don't forget when you lean with full tank--it get's leaner as the tank empties........... ken anderson................. Edited By ken anderson. on 19/05/2009 20:22:56 Quote Link to comment Share on other sites More sharing options...
Les Turrall 2 Posted May 19, 2009 Author Share Posted May 19, 2009 Hi Ken. Thankyou for your prompt reply. Will advise my collegue of your sound advice. Could find no debris in the motor and I tuned the carb if anything, a little rich. However, the amperage put through the plug on previous occasions could well provide the key. Again, many thanks. Les. Quote Link to comment Share on other sites More sharing options...
kiwi g Posted May 19, 2009 Share Posted May 19, 2009 WE found the asp 52 a great allround motor .The problem is that you probly are tuning it correct on the ground, but whats happening is the needle valve retaining clip is turning. pull it off and squeeze it up a little to tighten it on the shaft. your problems will be solved. we had the same problem buring plugs and didnt discover the proplem till one motor returned to the ground without a needle valve. Quote Link to comment Share on other sites More sharing options...
Les Turrall 2 Posted May 19, 2009 Author Share Posted May 19, 2009 Thankyou Graham. Will check this out and adjust as you suggest. I think this together with Kens suggestion re glowstarter amperage will crack it. Until very recently, the motor has been running perfectly. Thank you once again. Regards. Les T Quote Link to comment Share on other sites More sharing options...
Les Turrall 2 Posted May 21, 2009 Author Share Posted May 21, 2009 Hello Ken and Graeme. Have followed your suggestions and the engine is now running perfectly again. Very many thanks, my clubmate now regards me as a boffin!!!! Regards. Les T Quote Link to comment Share on other sites More sharing options...
kiwi g Posted May 22, 2009 Share Posted May 22, 2009 Les spread the word about the needle valve retaing clip its a common problem on many motors, leading to many engine outs in midair and pilot frustration. if you didnt see the clip turning under the vibration of the motor you would think its not tuned or has a blockage, . Great to hear you got it sorted.. Thanks kiwi G. Quote Link to comment Share on other sites More sharing options...
Jimbo565 Posted May 22, 2009 Share Posted May 22, 2009 Ken I'll show you how to do that one day,us old PPP ( penny pinchin pensioners ) have to be up to all the doges. PS Myron showed me how to do it. Jimbo Quote Link to comment Share on other sites More sharing options...
ken anderson. Posted May 22, 2009 Share Posted May 22, 2009 go on les the boffin.................well done......................... ken anderson....... jimbo---myron got the chimney pot's taken off the roof of his hoose - because he was given the smoke away for nowt................... Edited By ken anderson. on 22/05/2009 09:59:04 Edited By ken anderson. on 22/05/2009 10:00:11 Edited By ken anderson. on 22/05/2009 10:01:27 Quote Link to comment Share on other sites More sharing options...
Former Member Posted May 22, 2009 Share Posted May 22, 2009 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted May 22, 2009 Share Posted May 22, 2009 How about putting a piece of fuel tubing over the needle valve and jet tube -Never mind the weak spring clip thingy & also filing a little mark on the head of the needle valve so you can tell its position . There ! back on topic whilst they all keep taking the p--- out of me Quote Link to comment Share on other sites More sharing options...
kiwi g Posted June 11, 2009 Share Posted June 11, 2009 hey myron. if you put fuel tubing over the needle valve retaing clip thats turning on the shaft guess what happens. it still turns, then if you put a mark on the needle valve of a motor with a needle valve retaing clip that turns guess what happens. the mark moves with the clip.so lets mind the weak spring clip thingy that causes lots of problems to people who dont know why motors are running erratic. Quote Link to comment Share on other sites More sharing options...
onetenor Posted March 22, 2015 Share Posted March 22, 2015 Knurling or some other form of roughing the needle barrel helps too. Quote Link to comment Share on other sites More sharing options...
Tim Cheal Posted August 26, 2017 Share Posted August 26, 2017 Sorry to resurect an old thread, but I am having the same problem with an SC46. I have replaced the needle valve, and I know that is not turning loose (from observation on my test stand), but the engine is eating glow plugs. I have never had this happen before but you probably need a little bit of history. The engine is in my trainer (Boomerang) which has been laid up for about a year. When I resurected it the engine started fine, but failed to deliver full power on take off (it sounded fine but failed to pull the aircraft with any gusto). I took it apart and the rear bearing was very dirty and loose, so I replaced it. The new bearing was a very tight fit on the crank, but tapping with a bit of wood got it seated properly, and all went well rebuilding the engine. Since the rebuild it runs fine, and gets to full power again (APC 12 X 6 fitted). But, I have burnt out 2 plugs in quick succesion (OS No8 - I have tried cheap ones in other engines but they dont seem as reliable). When this happens the engine is hot, and smells lean - if you know what I mean. So, could a tight beraing cause the engine to lean off, or should I be looking at something else? Tim Quote Link to comment Share on other sites More sharing options...
onetenor Posted August 26, 2017 Share Posted August 26, 2017 I had this problem yrs ago on an engine that was not used for a while . I couldn't see owt wrong but just as an off chance twisted a drill with my fingers through the transfer port.It was surprising how much lacquer/varnish came out .On reassembly the engine ran fine with no more blown plugs. Seems as though the fuel transfer port wasn't Allowing enough fuel through causing the engine to run lean when hot. I could be entirely wrong but that 's what it seems like to me I had no idea beforehand that the ports were obstructed but took a chance and it paid off. Try it and see . John O/T . I Quote Link to comment Share on other sites More sharing options...
Tim Cheal Posted August 26, 2017 Share Posted August 26, 2017 That sounds like a good idea. I'll give it a go and let you know how I get on. Thank you. Tim Quote Link to comment Share on other sites More sharing options...
Tim Cheal Posted August 27, 2017 Share Posted August 27, 2017 Thanks John The transfer port looked pretty clear to me, I ran a cleaner up and down just to make sure, but thanks for the idea. Any other thoughts? Tim Quote Link to comment Share on other sites More sharing options...
Stuart Z Posted August 28, 2017 Share Posted August 28, 2017 Hi I have an SC46, only run 3 times from new and it's blown 3 plugs so far. I'm tempted to try an idle bar plug. Welcome any other ideas? S Quote Link to comment Share on other sites More sharing options...
ken anderson. Posted August 28, 2017 Share Posted August 28, 2017 hello Stuart-dont lean the motor out to the max....tune it with the main needle and then open it back out(rich) a click.....it'll lean out in the air as it unload's....... ken Anderson...ne..1...... unloaded dept. Quote Link to comment Share on other sites More sharing options...
Stuart Z Posted August 28, 2017 Share Posted August 28, 2017 Thanks Ken I'll remember to do that. It's an odd engine, I'm more used to OS engines, it never seems to peak - so possible it's over leaning at start that is causing the problem. It also seems a big prop recommended, 11x7, but one step at a time. Thanks again S Quote Link to comment Share on other sites More sharing options...
onetenor Posted August 28, 2017 Share Posted August 28, 2017 Posted by onetenor on 26/08/2017 15:15:50: I had this problem yrs ago on an engine that was not used for a while . I couldn't see owt wrong but just as an off chance twisted a drill with my fingers through the transfer port.It was surprising how much lacquer/varnish came out .On reassembly the engine ran fine with no more blown plugs. Seems as though the fuel transfer port wasn't Allowing enough fuel through causing the engine to run lean when hot. I could be entirely wrong but that 's what it seems like to me I had no idea beforehand that the ports were obstructed but took a chance and it paid off. Try it and see . John O/T . I Just in case try doing the same with crankshaft bore . In the off chance off course . No guarantees He He . John O/T Quote Link to comment Share on other sites More sharing options...
TIM Shaw Posted August 29, 2017 Share Posted August 29, 2017 I used to run SC 46s all the time - early ones. I always sealed the carb into the crankcase with epoxy, threw away the spring clip on the needle valve and fitted a short piece of fuel tubing over the needle / fitting. I ran 10 x 8 APC props, Duraglow 10% Nitro and Enya No 3 plugs and found them to be reliable and powerful. A club mate at the time was an Irvine fan, always used straight fuel and OS No 8 plugs and he had no problems either. Then it happened I bought an Irvine 46 on his recommendation, and he bought an SC 40 on mine. Neither of us had any success with these engines at all, I was doing a plug a flight and eventually we got so fed up we swapped - he got the Irvine, I got the SC. And all our problems went away. I think because Irvines liked the straight fuel and cold plug, SCs preferred a bit of Nitro and a hot plug. So I don't know if you have changed your fuel or plug rating, but I'd try reducing the prop size, 10% nitro and an Enya No3 plug. Quote Link to comment Share on other sites More sharing options...
Stuart Z Posted August 29, 2017 Share Posted August 29, 2017 Tim Thanks for that - I'll certainly try a No 3 as well as a number 8 hotter plug, makes sense to try. The prop also sounds worth a try, my SC46 never doesn't feel like it's getting the right rpm, I'll need to try a tachometer on it, but it sounds as if it is just not peaking, although I have Ken's advice also to take into account as well - allowing the motor to off load in the air. I also use 10% nitro. I'm sure the answer will be in there somewhere! Thanks folks for the input, valued as always. S Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted August 29, 2017 Share Posted August 29, 2017 You have good advice Stuart, you were over propped and over the years my only experience of plug failure was over voltage and debris in the cylinder. An SC 46 will run nicely on 5% fuel too, Edited By Denis Watkins on 29/08/2017 11:19:47 Quote Link to comment Share on other sites More sharing options...
Stuart Z Posted August 29, 2017 Share Posted August 29, 2017 Thanks Denis I always value the advice given. S Quote Link to comment Share on other sites More sharing options...
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