Large Model Association Forum

I have an old Z62 which was secondhand when I got it around 20yrs ago. It was fitted to a Super Duper Greenley used for glider towing and on a tow with the engine flat out it would suddenly stop after around a minute and a half, back on the ground it would start ok but do the same next time round. When not towing but just general flying using more throttle movements it wouldnt cut out.
Anyone else had similar problems or got any idea whats wrong with it?, the usual things of cleaning out the carb, changing the spark plug make no difference.

could it be getting a bit hot?

does it start to loose power befor it cuts or just stopp!?


try and richen the bottom end and top just a tad?


Allan

Hello Pat, as a long time user of Z62's I reckon your prob is due to the flexible flaps in the carb. After a while the stuff that the diaphragms are made of become less flexible and if not forced to move by opening and closing the throttle settings (as you said, the prob is not there when you use the throttle) the flow of fuel to the engine becomes incorrect and either floods or starves. Just thought the info may be usefull because have come across this prob myself. Anyway it would be worth getting the motor running properly because after 20 years it is just about run in!

Allan/Dave

Thanks for your answers, I dont suspect its getting hot as the problem occured during cooler weather and its a fully exposed engine that had been working faultlessly that hadnt been adjusted or fiddled with prior to the fault occuring. I will get a carb overhaul kit and try that, I want to put the engine in a new aerobatic plane I have on order and the Z62 will go nicely in it and as you imply Dave, its got plenty of life left in it yet

Pat