ORIGINAL: Pawel Rzedzicki
Hello!!!
I have a Saito 125, its has about 6 liters of fuel thru it. Previously it was in funtana s90 and now in Somenzini Yak 54 69". Its side mounted. During last flights i noticed it dies during idle. If i leaned lsn more it died rapidly, if i richened it died after 10-20 seconds. I was a little confused but once i noticed the throttle barrel has too big about 2 mm axial play (i dont know if this is a correct word- it moved in the carb along the lsn) I removed the little screw which end sits in the groove on the barrel. It apperaed it was too short and its end didnt get into groove deep enough. Because of it the end of the little screw had worn causing the barrel play. I found a similar screw, grinded its end to fit the groove and installed in the carb. I took the plane to a field, started engine, warmed it up and finally got stable perfect idle.
And thats the end of good news. Now i have a huge and first time in my life problem. When i tune the high speed needle with WOT i must turn off the HSN about 4 full turns!!!!!!!! I wouldnt care but it causes dramaticly rich midrange, almost deadly rich.
The only idea coming to my mind is: with defected throttle barrel leading screw i had to turn in the lsn too much to get pretty stable idle and now the needle comes into the sprayer too deep. If you have any other ideas please help me and give me some advices.
My LSN in turned 3 full turns in from flush with the throttle lever. How are yours?
Thanks, Pawel - after seeing your post I went and checked my 125 that I'd actually retired after about 2 litres of fuel. I could simply never get it to idle and rev - one was easy but it would not do both.
When I took it out of storage I noticed over 1mm of end play on the carb needle barrel. I removed the screw and the pictures show what I found - both sides had been worn flat! I turned a 3mm cap screw down at the end to fit closely and it now runs perfectly!
Richard