160FX midrange lean condition
08-06-2003, 11:03 AM
#1
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160FX midrange lean condition
I have a new 160 FX mounted horizontally in a OMP profile edge. It has almost 1 gal. of 18% Wildcat fuel through it.
My problem arises when I try to lean out my low & high needles. I get a terrible midrange detonation before I reach a satisfactory mixture on either needle. To get rid of this lean detondition at midrange I have to adjust the high & low needled very fat (rich), real fat.
I am running an untuned Mac's header with a mousse can pipe (I was waiting on a good breakin to tune the header). 18-6 MAC prop. A 14 oz. tank is mounted with the centerline of the tank in line to the aluminum joint on the remote needle valve. I can't get the tank any higher.
My question(s) to the wizards are:
1) Is there such a thing as a 3 needle carb for the 160fx? That would be the berries!
2) Would tank placement give this lean midrange condition? If so what way do I need to go.
3) Any other suggestions?
I have posted this to the profile planes forum also.
I have included 2 pics, in case i missed something.
Thanks in advance!!!
Stan
My problem arises when I try to lean out my low & high needles. I get a terrible midrange detonation before I reach a satisfactory mixture on either needle. To get rid of this lean detondition at midrange I have to adjust the high & low needled very fat (rich), real fat.
I am running an untuned Mac's header with a mousse can pipe (I was waiting on a good breakin to tune the header). 18-6 MAC prop. A 14 oz. tank is mounted with the centerline of the tank in line to the aluminum joint on the remote needle valve. I can't get the tank any higher.
My question(s) to the wizards are:
1) Is there such a thing as a 3 needle carb for the 160fx? That would be the berries!
2) Would tank placement give this lean midrange condition? If so what way do I need to go.
3) Any other suggestions?
I have posted this to the profile planes forum also.
I have included 2 pics, in case i missed something.
Thanks in advance!!!
Stan
08-06-2003, 02:10 PM
#3
My Feedback: (11)
160FX midrange lean condition
One major difficulty people have had with the 1.60 FX is making sure it has good fuel delivery. Some exhaust systems just don't give enough pressure.
If your engine can be tuned very rich at full throttle, then fuel delivery isn't a problem.
Please check the engine carefully. Is it really detonating in midrange? Or are you hearing exhaust resonance because the midrange RPM isn't right for the pipe tuning? Remember, the pipe is tuned for full-throttle RPM. Usually, an engine will trend rich in the midrange.
Unfortunately, O.S. does not make a 3-needle carb for the 1.60 FX.
If your engine can be tuned very rich at full throttle, then fuel delivery isn't a problem.
Please check the engine carefully. Is it really detonating in midrange? Or are you hearing exhaust resonance because the midrange RPM isn't right for the pipe tuning? Remember, the pipe is tuned for full-throttle RPM. Usually, an engine will trend rich in the midrange.
Unfortunately, O.S. does not make a 3-needle carb for the 1.60 FX.
08-06-2003, 02:27 PM
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160FX midrange lean condition
Bax:
I have made sure that fuel delivery was not an issue. I figured this motor sucks the full pretty rapidly. Oversize clunk, lines, ect. I have no problem tuning in a rich condition at full throttle.
What I might do is try a stock muffler (borrowed) and see if that helps / cures the problem.
If I still have the problem, well, i just don't know!!
Thanks for the quick reply.
Stan
I have made sure that fuel delivery was not an issue. I figured this motor sucks the full pretty rapidly. Oversize clunk, lines, ect. I have no problem tuning in a rich condition at full throttle.
What I might do is try a stock muffler (borrowed) and see if that helps / cures the problem.
If I still have the problem, well, i just don't know!!
Thanks for the quick reply.
Stan
