YS91FZ, need help with the Regulator setting.
02-16-2017, 11:03 AM
#1
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YS91FZ, need help with the Regulator setting.
Hey guys!
During the last few days I was trying to get my YS91FZ running smoothly.
Low speed is absolutely fine, high speed as well.
But I'm struggling a bit with the Regulator.
I was reading a lot of posts in this forum and tried the setting according to the information I read.
The problem is the following: From idle I increase the throttle slowly step by step and at about 4000 rpm the engine starts to smoke more than usual, then lowers the rpm and quits.
According to my understanding and also to what I read in this forum, this is a sign to be too rich on the regulator. Here I was 2,5 turns out from closed. (Flush is around 2 turns)
So I started to slowly close the Regulator step by step but in fact the same problem remained until I was at 1,5 turns out from closed.
And the engine doesn't sound nice at all with this lean Regulator setting.
So now I'm a bit confused as I thought that if the rpm drops and the engine starts to smoke more, it's too rich.
But it's almost impossible to be too rich with a Regulator open only 1,5 turns from closed?!
I have to say the engine was running smoothly and sounded best with the regulator open 2,5 turns. Transition over all is fine if I go from idle to full slowly, and it smokes quite well too. However, then the engine starts to suffer and quits if I stay in this rpm range of about 4000 for maybe 15 seconds.
Now I have to say I don't really know what to do and hope for any help here in the forum. :-)
Is it possible to be still too lean at 2,5 turns open? I thought if it was too lean the rpm would increase instead of drop and quit.
Also, how sensitive it this regulator? Can I do 1/8 turns or is it even more sensitive than that?
Regards from Switzerland!
During the last few days I was trying to get my YS91FZ running smoothly.
Low speed is absolutely fine, high speed as well.
But I'm struggling a bit with the Regulator.
I was reading a lot of posts in this forum and tried the setting according to the information I read.
The problem is the following: From idle I increase the throttle slowly step by step and at about 4000 rpm the engine starts to smoke more than usual, then lowers the rpm and quits.
According to my understanding and also to what I read in this forum, this is a sign to be too rich on the regulator. Here I was 2,5 turns out from closed. (Flush is around 2 turns)
So I started to slowly close the Regulator step by step but in fact the same problem remained until I was at 1,5 turns out from closed.
And the engine doesn't sound nice at all with this lean Regulator setting.
So now I'm a bit confused as I thought that if the rpm drops and the engine starts to smoke more, it's too rich.
But it's almost impossible to be too rich with a Regulator open only 1,5 turns from closed?!
I have to say the engine was running smoothly and sounded best with the regulator open 2,5 turns. Transition over all is fine if I go from idle to full slowly, and it smokes quite well too. However, then the engine starts to suffer and quits if I stay in this rpm range of about 4000 for maybe 15 seconds.
Now I have to say I don't really know what to do and hope for any help here in the forum. :-)
Is it possible to be still too lean at 2,5 turns open? I thought if it was too lean the rpm would increase instead of drop and quit.
Also, how sensitive it this regulator? Can I do 1/8 turns or is it even more sensitive than that?
Regards from Switzerland!
09-06-2017, 01:25 PM
#3
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I had a YS 63FZ (regulator underside crankcase) that drove me nuts, with the same problems you describe.
I gave in after trying all mixture settings and replaced the diaphragm, silicone regulator plunger and spring.
The engine ran perfectly well after that, and is still a great runner today.
I gave in after trying all mixture settings and replaced the diaphragm, silicone regulator plunger and spring.
The engine ran perfectly well after that, and is still a great runner today.
