Colin Anderson Posted January 24, 2014 Share Posted January 24, 2014 Desperately seeking help with an Irvine 40 glow engine (R/C). My engine will not run for more than a few minutes before slowing down and stopping. I'm assuming that there is a loss of pressure somewhere, but I'm at a loss as to where to look. I've checked the fuel line the vent line and the one from the silencer - all are secure. I've tightened up the screw to the tank bung, nothing seems to make a difference. This is a new engine and has been run in on a test bench with no problems. The symptoms only started after the second flight in the airframe. Any suggestions? Please! Quote Link to comment Share on other sites More sharing options...
John Privett Posted January 24, 2014 Share Posted January 24, 2014 Colin, a bit of background info might be useful. Are you experienced with glow engines, or is this your first one? It might just that it's running a little too lean, or it may be a rather more subtle problem. And particularly if it's new, it will need to run initially a little on the rich side to break it in. Quote Link to comment Share on other sites More sharing options...
John Tee Posted January 24, 2014 Share Posted January 24, 2014 Colin, Have you checked the nipple on the silencer is clear? If blocked you will end up with a partial vacuum in the fuel tank. Try running the engine without the pipe connected to the nipple, it may need adjusting to run properly. John Quote Link to comment Share on other sites More sharing options...
Colin Anderson Posted January 24, 2014 Author Share Posted January 24, 2014 Hi John, Thanks for the reply. I'm not new to glow engines, but am new to R/C ones. The engine has been run in and experienced no problems. It is at present still running rich. At tick over it will quite happily run until the tank is empty. There is no hesitation on opening the throttle from idle up to full throttle. However, after running at maximum revs for a few minutes the engine gradually slows and dies - if quickly returned to idle it will continue to run OK. Quote Link to comment Share on other sites More sharing options...
cymaz Posted January 24, 2014 Share Posted January 24, 2014 Richen the high speed needle 3-4 clicks and recheck. That's all I can think of to help. Edited By cymaz on 24/01/2014 22:39:09 Quote Link to comment Share on other sites More sharing options...
Colin Anderson Posted January 24, 2014 Author Share Posted January 24, 2014 Once again John, thanks. No, I haven't checked the silencer nipple for blockage; I didn't know it could block! What would block it? Removing the pipe from the silencer nipple produces the same symptoms (only quicker) as the Irvine requires a pressurised tank in order to run. I will, however, check the silencer nipple tomorrow, as you suggest. If it turns out to be that simple I'll be forever in your debt because I'm pulling out my hair here! Quote Link to comment Share on other sites More sharing options...
cymaz Posted January 24, 2014 Share Posted January 24, 2014 How old is the glow plug?? If old renew. This will rule another possible problem. Quote Link to comment Share on other sites More sharing options...
Willyuk Posted January 24, 2014 Share Posted January 24, 2014 Is the engine running hot? Check after it stops that the engine is not overheating, smell sometimes is a clue. I had this with a glow engine where the cowl was not allowing sufficient airflow, ran fine at low revs but a short while under full power and it died. Solution was simple, increase venting. Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted January 24, 2014 Share Posted January 24, 2014 what model do you have it in Colin? how far away is tank, and is centre of tank inline with carb you say it ran ok on test bench, so whats changed? Quote Link to comment Share on other sites More sharing options...
Colin Anderson Posted January 24, 2014 Author Share Posted January 24, 2014 OK guys, firstly the glow plug is new - same as the engine. Secondly: define hot. Certainly you wouldn't want to hold the cylinder for long! However, burning smell, no and the cylinder is out in the open, upright in a Piper Cub. The tank is directly behind the engine. Yes, the centre line of the tank is a little below the carb centre line, but not by much and the tank is pressurised by the exhaust. For the model's first flight it ran perfectly well for around ten minutes. Quote Link to comment Share on other sites More sharing options...
iqon Posted January 24, 2014 Share Posted January 24, 2014 has the Cub got a cowl, if so may need more airflow. Quote Link to comment Share on other sites More sharing options...
Colin Anderson Posted January 24, 2014 Author Share Posted January 24, 2014 As stated above: the cylinder sits out in the airflow. Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted January 24, 2014 Share Posted January 24, 2014 take main needle out and flush it out (pump direct to nipple) may have picked bit of dirt up make sure all bolts and screws are tight on engine, check filter if you using one, if no joy, strip tank and check for leaks in pipes. (is it same tank as test bed) Quote Link to comment Share on other sites More sharing options...
Colin Anderson Posted January 24, 2014 Author Share Posted January 24, 2014 Hi John, I'm not using a filter; perhaps I should? The tank in the plane is not the same one used on the test bed, but again is new. There are no obvious leaks in or around the pipes. However, I will take the main needle out and flush as you suggest. Perhaps some of the gunk that the exhaust pumps out has got into the fuel via the nipple? It's a possibility I hadn't thought of; why would that only effect the high speed ruining though and not the idle? Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted January 24, 2014 Share Posted January 24, 2014 it ran o.k before only tank has changed ?? very easy to nick pipes or get one with a kink in you got any bubbles in feed pipe when its running Quote Link to comment Share on other sites More sharing options...
Colin Anderson Posted January 25, 2014 Author Share Posted January 25, 2014 Hi John, Yes it ran perfectly before, both on the test bed and in the model with its present tank. There are no kinks or nicks in the lines (first thing I checked) and no air bubbles in the line. It's quite odd because, as I said, it ran faultlessly for the first flight, but not for the second! Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted January 25, 2014 Share Posted January 25, 2014 all I've got left then is change the plug Colin and hope for the best Quote Link to comment Share on other sites More sharing options...
David Davis Posted January 25, 2014 Share Posted January 25, 2014 We had a similar problem at the club last year with a different two stroke engine. We tried everything, then just before the owner gave up, another member offered him a tankful of fuel. The tank was drained, refilled with 20% nitro and the engine ran perfectly! I use Model Technics F7 glowplugs in everything including fourstrokes, I've never had a problem with them. Quote Link to comment Share on other sites More sharing options...
.. Posted January 25, 2014 Share Posted January 25, 2014 Hi Colin, I presume this is the same Irvine that you ran in at the end of last year? The running in process can destroy your plug so this would be my first port of call. An OS number 8 suits this engine nicely, Secondly as mentioned are you sure your fuel is good? When you say it die's is that at tickover or whilst reving? J... Quote Link to comment Share on other sites More sharing options...
Paul Jefferies Posted January 25, 2014 Share Posted January 25, 2014 It does sound as though it is overheating, perhaps it is just not run in yet. Some engines can take several hours running before they are properly run in. You say you have run it on the bench....... For how long? In the air it will unload and reach higher revs and probably higher temperatures than on the bench. Try some more bench running and after an hour or two, if all seems well, reduce the size of the prop in order to increase the revs/temperature....... and of course go back to the bigger prop when you put it back in the model. Paul Quote Link to comment Share on other sites More sharing options...
Stevo Posted January 25, 2014 Share Posted January 25, 2014 Whip it all out and put it on a test stand - or reinstall. Do everything that has been suggested, it's far easier on a stand! Check for the carb barrel sticking etc, I did have one with a VERY unstable idle once and the barrel return spring was missing!! In the main, an Irvine is a fit-and-forget engine. Regards flushing - go to your car spares store and buy a can of carb flushing (Toluene). That way you can jet it all out under pressure - but watch your eyes and dont use it near an open flame... Quote Link to comment Share on other sites More sharing options...
Colin Anderson Posted January 25, 2014 Author Share Posted January 25, 2014 Thanks for all the help guys. Today I followed John's suggestion and flushed both the exhaust nipple and the main jet and fired up the engine. I've put through two full tanks. For the first tank I varied the throttle throughout the run; I then filled up again and ran the engine at full throttle, until the tank emptied - nearly 15 minutes. In both cases the engine ran fine, so either gunk in the exhaust nipple or in the main jet seems to have caused the problem. I still think the engine is running too rich, as the airframe is getting liberally coated in black, oily sludge, but I think for now I'll leave the secondary jet alone. I had previously tried to adjust the secondary jet, but without success, due to the running problems. Perhaps I'll get one of the more knowledgable members to adjust it for me. I did notice today that once I get the throttle stick at just over halfway that opening further doesn't seem to have much effect. I've recently fitted a 12 inch prop in place of the 11 inch and am wondering if this would make the difference. Regarding the fuel: yes, there had been a change in fuel. Previously I ran the engine on GN 5 ( which was years old); when I bought a new bottle I bought sport 5 (Irvine blend) which I presume is specifically for Irvine engines. Personally I think it ran better on the old GN 5; it certainly started easier, especially when hot. I have no idea what the difference is between these two fuels as it doesn't say what the nitro content is, but I'm assuming that GN 5 is a 5% nitro mix. The glow plug I'm using is an OS 8. Quote Link to comment Share on other sites More sharing options...
crispin church Posted January 25, 2014 Share Posted January 25, 2014 12" way to big for 40 11x5 max Quote Link to comment Share on other sites More sharing options...
Stevo Posted January 25, 2014 Share Posted January 25, 2014 Well spotted I've got away with a 12x4 before on a 40 - More by luck I think. 11x5 or 11x6 is fine - my Cubbie had a Saito 56 & 11x6. More than enough. Colin - I ran my old Irvine on "Contest 10" - purred like a kitten. Edited By Stevo on 25/01/2014 13:44:17 Quote Link to comment Share on other sites More sharing options...
Martin Whybrow Posted January 25, 2014 Share Posted January 25, 2014 Black oily deposits mean the engines not run in yet, that's a sure sign that aluminium particles are still being produced. Quote Link to comment Share on other sites More sharing options...
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