I purchased an OS 95 AX about four months ago. I installed it in a Wot4 XL using its own exhaust, own plug and mounting it on its side. It ran fine on the ground, but after 3 to 4 minutes of flight cut out on a regular basis.
After seeing this thread I then used a type F plug which eliminated the problem. I have recently put the engine into a Seagull Zlin 50, again side mounted but this time with a Just Engines Pitts silencer.
Its reverted back to the old problem. I am still using the type F plug, I have even tried the bar type. I have checked the plumbing and asked several different flyers to set up the needles as they would normally do but it still stops at around 3 -4 minutes and with about half throttle.
Any ideas?