Hi everyone, i am new to ultralights (i was only flying skyhawks and
warriors until now). i now own Fisher ultralight with Rotax 277. i
never flew it, i never saw it flying and i do not know previous owner
who actually flew it. when i got the airplane it had carb removed but everything else looks in good shape. i put carb back and was able to successfully start the engine. engine runs nice and smooth at 4000
rpm or above, but when it drops below 4000 it starts shaking badly.
it runs stable but shakes to the point that some screws from the
panel shook out. i have read that single cylinder 2 strokes shake a
lot, but to me it looks too excessive. i took a prop off and it runs
much smoother without it. i am thinking prop may be out of balance?
the problem is that i do not have any experience or knowledge to tell
how much vibration is too much on those engines. does anyone know how
to determine if this vibration is normal?
On 06/29/2020 03:09 PM, wrote:
Hi everyone, i am new to ultralights (i was only flying skyhawks and warriors until now). i now own Fisher ultralight with Rotax 277. i
never flew it, i never saw it flying and i do not know previous owner
who actually flew it. when i got the airplane it had carb removed but everything else looks in good shape. i put carb back and was able to successfully start the engine. engine runs nice and smooth at 4000
rpm or above, but when it drops below 4000 it starts shaking badly.
it runs stable but shakes to the point that some screws from the
panel shook out. i have read that single cylinder 2 strokes shake a
lot, but to me it looks too excessive. i took a prop off and it runs
much smoother without it. i am thinking prop may be out of balance?
the problem is that i do not have any experience or knowledge to tell
how much vibration is too much on those engines. does anyone know how
to determine if this vibration is normal?
There's a link for tech support at https://fisherflying.com/
The prop could be balanced perfectly, and have the flex or mass to
interact unfavorably with the engine, engine mount, speed-reduction
drive. Or anything else.
On 06/30/2020 03:39 AM, Remi Dargis wrote:I had a Rotax 277, and it purred like a kitten, even when at low RPM's. Checking the prop for balance should be fairly easy, then I would make the gear box my next point of attention. The 277 can be a great little engine. Maybe also, check the engine
On Tuesday, June 30, 2020 at 12:01:55 AM UTC-4, Corvid wrote:
On 06/29/2020 03:09 PM, wrote:
Hi everyone, i am new to ultralights (i was only flying skyhawks
and warriors until now). i now own Fisher ultralight with Rotax
277. i never flew it, i never saw it flying and i do not know
previous owner who actually flew it. when i got the airplane it
had carb removed but everything else looks in good shape. i put
carb back and was able to successfully start the engine. engine
runs nice and smooth at 4000 rpm or above, but when it drops
below 4000 it starts shaking badly. it runs stable but shakes to
the point that some screws from the panel shook out. i have read
that single cylinder 2 strokes shake a lot, but to me it looks
too excessive. i took a prop off and it runs much smoother
without it. i am thinking prop may be out of balance? the problem
is that i do not have any experience or knowledge to tell how
much vibration is too much on those engines. does anyone know
how to determine if this vibration is normal?
There's a link for tech support at https://fisherflying.com/
The prop could be balanced perfectly, and have the flex or mass to
interact unfavorably with the engine, engine mount,
speed-reduction drive. Or anything else.
my problem is that i don't know how much vibration is consider4000 sure sounds high for banging and shaking. I know what I'd replace
"normal". i am reading online that others are complaining about 277 shaking, some say this is normal and just a nature of this motor. i
don't want to start replacing things if this is normal. is there any criteria, anything to determine if this is normal? that shaking
sounds like "compression vibration" - makes one bang on every stroke.
or if you turn ignition off at higher rpm, when it starts to wind
down below 4000 starts banging and does that till the last stroke
when it stops.
if that's normal.
crossposted to rec.aviation.homebuilt , a once-bustling group which
still has lurkers waiting for questions like this.
On Tuesday, June 30, 2020 at 11:54:16 AM UTC-5, Corvid wrote:mounts, so insure that they are in good shape, and snugged evenly. Only problem with that motor is, with only 1 piston, if anything goes wrong (like when the rings went out on mine), the sky can become a REALLY lonely place.
On 06/30/2020 03:39 AM, Remi Dargis wrote:
On Tuesday, June 30, 2020 at 12:01:55 AM UTC-4, Corvid wrote:
On 06/29/2020 03:09 PM, wrote:
Hi everyone, i am new to ultralights (i was only flying skyhawks
and warriors until now). i now own Fisher ultralight with Rotax
277. i never flew it, i never saw it flying and i do not know
previous owner who actually flew it. when i got the airplane it
had carb removed but everything else looks in good shape. i put
carb back and was able to successfully start the engine. engine
runs nice and smooth at 4000 rpm or above, but when it drops
below 4000 it starts shaking badly. it runs stable but shakes to
the point that some screws from the panel shook out. i have read
that single cylinder 2 strokes shake a lot, but to me it looks
too excessive. i took a prop off and it runs much smoother
without it. i am thinking prop may be out of balance? the problem
is that i do not have any experience or knowledge to tell how
much vibration is too much on those engines. does anyone know
how to determine if this vibration is normal?
There's a link for tech support at https://fisherflying.com/
The prop could be balanced perfectly, and have the flex or mass to
interact unfavorably with the engine, engine mount,
speed-reduction drive. Or anything else.
my problem is that i don't know how much vibration is consider4000 sure sounds high for banging and shaking. I know what I'd replace
"normal". i am reading online that others are complaining about 277 shaking, some say this is normal and just a nature of this motor. i don't want to start replacing things if this is normal. is there any criteria, anything to determine if this is normal? that shaking
sounds like "compression vibration" - makes one bang on every stroke.
or if you turn ignition off at higher rpm, when it starts to wind
down below 4000 starts banging and does that till the last stroke
when it stops.
if that's normal.
crossposted to rec.aviation.homebuilt , a once-bustling group whichI had a Rotax 277, and it purred like a kitten, even when at low RPM's. Checking the prop for balance should be fairly easy, then I would make the gear box my next point of attention. The 277 can be a great little engine. Maybe also, check the engine
still has lurkers waiting for questions like this.
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