MVVS 58 butterfly opening at full throttle
02-25-2006, 05:22 PM
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MVVS 58 butterfly opening at full throttle
Should the carb be set up so that the butterfly in the carb can move from almost closed to fully open?
I am working on my throttle curve and noticed that my butterfly wasnt opening all the way, I remember when I first started running the motor that it wouldnt run fully open, so I set the ATV to limit the throttle and closed off the butterfly some.
I am now thinking that I have been robbing the motor of its full potential and mabey I was not rich enough at full throttle. Or, could it be that the motor does not respond at all when the butterfly is opened past 3/4.
I am working on my throttle curve and noticed that my butterfly wasnt opening all the way, I remember when I first started running the motor that it wouldnt run fully open, so I set the ATV to limit the throttle and closed off the butterfly some.
I am now thinking that I have been robbing the motor of its full potential and mabey I was not rich enough at full throttle. Or, could it be that the motor does not respond at all when the butterfly is opened past 3/4.
02-25-2006, 06:07 PM
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RE: MVVS 58 butterfly opening at full throttle
The last bit of valve travel hardly influences the power. This is typical for the Walbro carbs on RC engines.
You must set the needles. Factory settings are such, that they allow starting the engine, but the setting is in no way perfect. [link=http://www.prme.nl/forum/viewtopic.php?t=10]Look here how to do that.[/link]
You must set the needles. Factory settings are such, that they allow starting the engine, but the setting is in no way perfect. [link=http://www.prme.nl/forum/viewtopic.php?t=10]Look here how to do that.[/link]
02-25-2006, 09:49 PM
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RE: MVVS 58 butterfly opening at full throttle
Preivers
Thanks, I did all that once but only from closed to about 3/4 open throttle. I reset the ATV on the throttle so that the butterfly now openes all the way with no servo binding. I then started the engine (let it warm up) and set the low speed needle till I had a good idle and transition. However, the motor would now die at wide open throttle position as it was now fully open and the mixture was too lean. I opened the high speed needle untill I could sustain wide open throttle and then opened it an additional 1/16. I then checked the throttle response from idle to wide open and it was nice and crisp. I have a little four stroking between high idle and 1/4 throttle so I think this is acceptable, also now I attain max rpm at almost full stick position. This now gives me a much better throttle curve with more points from idle to wide open. I dont think I have it perfectly set up yet but I think it is now acceptable and ready to fly again.
Thanks, I did all that once but only from closed to about 3/4 open throttle. I reset the ATV on the throttle so that the butterfly now openes all the way with no servo binding. I then started the engine (let it warm up) and set the low speed needle till I had a good idle and transition. However, the motor would now die at wide open throttle position as it was now fully open and the mixture was too lean. I opened the high speed needle untill I could sustain wide open throttle and then opened it an additional 1/16. I then checked the throttle response from idle to wide open and it was nice and crisp. I have a little four stroking between high idle and 1/4 throttle so I think this is acceptable, also now I attain max rpm at almost full stick position. This now gives me a much better throttle curve with more points from idle to wide open. I dont think I have it perfectly set up yet but I think it is now acceptable and ready to fly again.
