It seems the YS engines forum is dead so I'm posting this here.....

The used DZ170 I purchased is my second, after a 140DZ, YS fuel injected engine. The 170 has a different fuel injector than the 140 does. What is the purpose of the diaphragm? Is it a check valve of some sort? I'm not seen it listed as a repair item unless it is in a "kit" with other parts. My diaphram looks a bit funky but I believe it is still functional???

My 170 was completely disassembled. It was in reasonably good shape with a few minor issues. I found a bent exhaust valve push rod and a little more varnish than expected. Valve clearance was excessive on the intake and of course on the exhaust. A 140 parts engine donated an exhaust pushrod.

After reassembly I feel the compression is a bit on the low side and can hear compression loss through the crankcase indicating a poor ring seal. The ring has an end gap of about .008. Is this to much? I have to guess it is on the high side of tolerance. Maybe running will improve the compression????

Thanks!

Ken

The valve on the injector removes air from the line.

You should replace the ring with a new one if you hear the compression going down the crankcase, this engines when the ring is worn it will loose about half the power when they get to temperature in flight.

This engine will better work with Cool Power 30% high performance heli fuel, or it will most likely flame out eventually.

Regards