Hi,
Wondering if some on has an idea here? My YS 160 DZ has developed a problem in that it now leans out badly and all efforts to fix it have so far failed. The engine has been running well for almost a year but at the last comp it stopped and I failed to get it going again. I found that one of the very small springs that sit behind the small plastic valves in the fuel pump was broken, so this has been replaced. The engine now runs but it constantly leans out when I try to increase the throttle. Tthe high speed valve is wound out 2 turns, so this should be more than enough as it used to be 1 and half turns before this problem started. The regulator is now screwed in much more than it should be in an effort to richen the transition, still no good. All rubber O rings and gaskets have been replaced and all efforts have been made to find a blockage somewhere, nothing found and I used my air compressor to blow through all passage ways to be sure. Whats even worse is that it will some times run just fine for one flight then this problem starts all over again, is driving me nuts. Hope some on out there has a clue as I have run out of ideas.

Cheers,
Jeff

this is the classic pattern forum (.60 - .90 size). try the pattern forum for modern engine questions. good luck.

Jeff - Check the YS support forum here on RCU and do a little searching there. I'm sure you will find an answer. Here is the link tothe forum

http://www.rcuniverse.com/forum/forumid_197/tt.htm

Thanks for the heads up, cheers

Thread moved to Pattern Flying Forum

Ken

Jeff,
I had the same problem on a YS 140DZ. I rebuild the pump new diaphram, gaskets, springs and the little valves. The engine would run fine at idel and to about 60% throttle and then air would start coming out of the pump and causing the engine to lean out. I did the same as you and replaced valve cover gaskets and all the o-rings and still the same problem. What the problem was is the pump housing was worn out and the only thing you can do is replace the whole pump unit. I made sure the fuel flow had no air coming to the pump and when I replaced the pump the engine ran perfect. If you install a new pump unit reset all of your settings on the needle at 2 turns out and the regulator screw flush with the housing then retune from there.

I hope this helps
Larry

Hi Larry,
As luck would have it I managed to talk to a fella here in Oz who is also a wealth of knowledge with these most perplexing beasties and he suggested the same thing. Also suggested a few other things to check, like the hose between the regulator and the crank case that supplies pressure to the regulator. You know I had already changed it but thought, well can't hurt to change it again with fresh hose off the roll. Bugger me if the engine now seems to be running a treat, all settings are now back to where they should be, but the real test is in the air and that will have to wait til the weekend. Will let you know the out come. Thanks heaps for the info. This is the first time I have posted to this forum, it's great will be back for sure.

Cheers
Jeff

Hi jeff

why dont you send the engin to Will Crossman in VIC, I m sure he can get it fix for you...

Patrick S

Hi Patrick,
Thanks for the tip, but I reckon if I'm gonna run this type of engine I need to learn its secrets. After lots of work and cursing this last month has brought forth lots of new knowledge about this engine. Flew the Cyclone 2x2 with the 160 DZ on the weekend, its running sweet, the idle is really soft and as you might guess I'm loving it?

Cheers
Jeff