Help with 3W 75i
03-01-2009, 03:59 AM
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Help with 3W 75i
I bought a "new" 75i here on RCU several months ago and just now getting ready to use it....the seller did not tell me it is 6-7 years old and being new to gas engines I didn't know anybetter. My PROBLEM is the carb is a Tillotson which is difficult to connect to servos, this I can maybe live with, depending on how engine runs.........the other problem is that the ignition is a 4.8 volt version with a battery connect plug I've never seen before, this is a pre 2003 version......can I make this work? Any experience with or knowledge would really help.................Thanks WC
03-01-2009, 08:02 AM
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RE: Help with 3W 75i
Hi,
Most gas carbs need an arm attached to the carb "wheel" to get the throw and precision required for flight. I use a modified long servo arm which is clipped to fit. Arm is then bolted to the carb "wheel arm" with a 2-56 bolt. Then the interface between the servo arm and the carb arm is glued with medium ca and hit with accelerator.
The ignition may have the standard 3W molex. I always clip it off and use a Radio shack molex. I always solder the molex on.
Hope this helps
Elson
Most gas carbs need an arm attached to the carb "wheel" to get the throw and precision required for flight. I use a modified long servo arm which is clipped to fit. Arm is then bolted to the carb "wheel arm" with a 2-56 bolt. Then the interface between the servo arm and the carb arm is glued with medium ca and hit with accelerator.
The ignition may have the standard 3W molex. I always clip it off and use a Radio shack molex. I always solder the molex on.
Hope this helps
Elson
03-01-2009, 09:19 AM
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RE: Help with 3W 75i
The origin of the connector you are looking at is a Tamiya connector like the electric car guys used to use with the big nicad battery packs. Like Elson says, you can easily cut it off and use something else.
Another thing here, if your ignition module has a blue dot sticker on it, it is safe to use with a 6V pack if you choose to do so, otherwise you are limited to 4.8V
Aircraft international sells some steel throttle arms that must be soldered to the existing carb arm, I like to use these, but you must be very careful when soldering, I use a propane torch and a very steady hand
.
Another thing here, if your ignition module has a blue dot sticker on it, it is safe to use with a 6V pack if you choose to do so, otherwise you are limited to 4.8V
Aircraft international sells some steel throttle arms that must be soldered to the existing carb arm, I like to use these, but you must be very careful when soldering, I use a propane torch and a very steady hand
.
03-01-2009, 12:10 PM
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RE: Help with 3W 75i
I have used my Weller soldering gun to attach the arm to the carb. Another option is to grind off the arm and attach a plastic steering arm to the carb. ( http://www3.towerhobbies.com/cgi-bin...&I=LXD849&P=ML) I leave the spring on.
03-01-2009, 01:34 PM
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RE: Help with 3W 75i
Well the good news is the ignitions dos have the blue dot so I can use the 6v battery...I'll have to see how the tillotson carb does.................Thanks for the help..WC
