Please help me diagnose my engine problem!
Engine is an ASP 46. Got it used from a guy who claimed it didn't have much mileage on it.
Idle on the engine was set very rich, so I leaned that out considerably. After tuning, the pinch test on idle as well as full throttle results in RPM's speeding up, so all good. Temps measured with infrared thermometer comes in at about 70-80 (160 - 175 deg F) degrees Celcius on idle and up to a max of about 105 degrees (221 deg F) on full throttle. Exhaust is dumping a lot of oil, so must be rich enough. I am using "80/20 castor straight". Glow plug is medium heat and brand new.
After about 5 mins of mostly idling, the RPM's drop a little and I can hear the engine struggling. If I then throttle up too fast the engine just dies. This happens consistently after 5 minutes, every time. Compression is good when the engine is cool, but when the engine dies, it is way reduced. Motor does not start again until 5-10 minutes later when it has cooled down. I tried dumping some fuel on the carb and inlet to cool it down, but this doesn't seem to work.
Any idea what is wrong? Thanks in advance!