FS120-II with pump not consistent
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FS120-II with pump not consistent
I have an fs120 with a pump that I cannot get to run consistently. If i follow the instrustions to set the needle valve it will run wide open for a while but will not idle for long before going dead. If I lean it then it will idle fine but seems like it is starved for fuel on the top end and eventually goes dead. The low speed valve is set completely lean at about 4 oclock.
My usual scenario is that it starts immediately at a high idle and when I remove the glow plug it goes dead. I then lean the high speed needle and the engine restarts and stays running out to the runway but about the time i get to 50% throttle it starts trying to go dead so I have to try and land. If I try again with a rich setting and keep it at a very high idle I can fly for a while but it eventually goes dead.
I am using 15% fuel that is all synthetic and either a 15X8 or 16x6 prop, the cowl is off the plane so I know there are not any bubble of foaming happening on the ground. This motor is quite frustrating so any help would be appreciated.
Tim
My usual scenario is that it starts immediately at a high idle and when I remove the glow plug it goes dead. I then lean the high speed needle and the engine restarts and stays running out to the runway but about the time i get to 50% throttle it starts trying to go dead so I have to try and land. If I try again with a rich setting and keep it at a very high idle I can fly for a while but it eventually goes dead.
I am using 15% fuel that is all synthetic and either a 15X8 or 16x6 prop, the cowl is off the plane so I know there are not any bubble of foaming happening on the ground. This motor is quite frustrating so any help would be appreciated.
Tim
#2
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RE: FS120-II with pump not consistent
We usually start out with the high-speed needle opened about one turn out from closed. You will lean it from there. Here's how we set the pumped engines:
http://www.osengines.com/faq/faq-pumped.html
http://www.osengines.com/faq/faq-pumped.html
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RE: FS120-II with pump not consistent
I have tried the faq but I can't get an idle and a high speed run. If I put the high speed needle at about 1 turn it idles well and has some low end but if i open the throttle all the way the engine loses rpm and dies. If I open the high speed needle a click or two it is the same story, but if I open another click it runs fine on the high end but goes dead at idle. I am using 3/32 id fuel tubing would that cause any restriction on the high end?
Tim
Tim
#4
My Feedback: (11)
RE: FS120-II with pump not consistent
You must have the high-speed needle as LEAN as you can get it without detonation or RPM drop. Usually, that means that the high-speed needle will be about 3/4-turn or so out from closed. Only then will you be able to set a reliable idle.
If nothing at all works, then it's likely that the regulator is not working properly. Unfortunately, that's part of the carburetor body, and that's a part that's no longer available from us or O.S. in Japan.
If nothing at all works, then it's likely that the regulator is not working properly. Unfortunately, that's part of the carburetor body, and that's a part that's no longer available from us or O.S. in Japan.
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RE: FS120-II with pump not consistent
Is there an exploded view of the carburetor or a way to visually tell if the regulator is in good shape. I assume that is the plastic diaphram on the back of the carb. This engine has been taken apart and cleaned after being in storage for a few years but it ran well for about 2 months and now will not do right no matter what. I will try different needle settings this weekend and see where it ends up.
Thanks,
Tim
Thanks,
Tim
#6
My Feedback: (11)
RE: FS120-II with pump not consistent
An exploded diagram of the carburetor will not show the regulator. The regulator was built into the carburetor body by the factory, and so was only seen externally in the parts diagrams. To get a new regulator, one had to purchase an entire carburetor body. They were not sold separately.