High Idle Vibration Brison 3.2 HELP!
11-10-2002 | 01:41 AM
#1
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From: North Saanich,
BC, CANADA
High Idle Vibration Brison 3.2 HELP!
Good Day All,
I have a Brison 3.2, just installed on a 29% Giles 202. The prop is well balanced. Then engine will vibrate quite badly at idle and smooths out considerably when the throttle is advanced. At full throttle the vibration is acceptable.
Additionally, in the midrange speeds the engine tends not to run very smoothly (sounds rough). The vibration at midrange speeds is not a problem.
I've been reading other posts and get the opinion that my low end mixture might be too rich.
Any Suggestions?
Cheers,
Marcus.
I have a Brison 3.2, just installed on a 29% Giles 202. The prop is well balanced. Then engine will vibrate quite badly at idle and smooths out considerably when the throttle is advanced. At full throttle the vibration is acceptable.
Additionally, in the midrange speeds the engine tends not to run very smoothly (sounds rough). The vibration at midrange speeds is not a problem.
I've been reading other posts and get the opinion that my low end mixture might be too rich.
Any Suggestions?
Cheers,
Marcus.
11-10-2002 | 05:28 AM
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From: Locust Grove,
GA
High Idle Vibration Brison 3.2 HELP!
My engine did this and I was able to lean the low end by over 1/2 turn. I how much fuel do you have through the engine? If you have consumed several gallons, I would recommend that you re-tune the engine.
11-10-2002 | 07:50 AM
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From: North Saanich,
BC, CANADA
High Idle Vibration Brison 3.2 HELP!
Thanks for the info Geistware 
Does anybody else have any other comments on this issue?
By the way.... this engine only has about 2 or 3 gallons of fuel through it.
Cheers,
Marcus.
Does anybody else have any other comments on this issue?
By the way.... this engine only has about 2 or 3 gallons of fuel through it.
Cheers,
Marcus.
11-10-2002 | 02:44 PM
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From: Hammond,
IN
High Idle Vibration Brison 3.2 HELP!
Try leaning the low end needle about 1/4 turn. Then try acceleration from idle to about 1/3rd throttle. If the engine gasps, then it's too lean. Keep leaning the low end needle and recheck acceleration. When you get snappy acceleration, the low end is correct. After setting the low end, readjust the high end needle for full throttle max rpm with a tach. Then open the high end needle slightly so the max rpm falls by about 100 rpm. This insures that the mixture is not too lean. Test fly. Make sure it doesn't sag in the verticals. If it sags, richen the top end needle slightly.
11-11-2002 | 07:22 AM
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From: North Saanich,
BC, CANADA
High Idle Vibration Brison 3.2 HELP!
The Giles is an Ultimate Sport G202. The fuselage is made of fiberglass, the wings are of sheeted foam.
I'll try leaning the low idle adjustment tomorrow.
Cheers,
Marcus.
I'll try leaning the low idle adjustment tomorrow.
Cheers,
Marcus.
11-12-2002 | 08:13 PM
#8
High Idle Vibration Brison 3.2 HELP!
Diablo hit the nail on the head. If you do what he says you should be fine. Brisson does reccomend Premium fuel and synthetic oil. I have used both types of oil with no differance. However it does run better on premium fuel. After it breaks in it will also run smoother. After about 24hrs of run time you will have gained about 500 rpm's
