2500 problems
04-06-2002, 05:29 PM
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2500 problems
I have an ST 2500 in a Byron Christen Husky. It runs very well on the ground but once in the air when running at 1/2 throttle, it sputters a lot. I'm using Omega Super "T" fuel. Any advice you can give me would be appreciated.
04-08-2002, 10:56 AM
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2500 problems
Alan,
How much run time does the engine have? How much time do you spend at half throttle in flight?
This is some basic info from our engine techs on the big tigres. Please let me know how this compares to what you've tried:
Once your BIG SuperTigre has a gallon or two of regular fuel run through it, you can use one of the so-called "SuperTigre, or Super-T" fuels, which have 10%-12% oil content. Keep Nitro 10% or lower for best operation.
To properly set up your carburetor, there are a few steps...
Make sure the spraybar is set so that the fuel slot is pointed straight down the center of the carburetor. You will have to look through the carb from the bottom, with the venturi opened to full. Loosen the two screws next to the high-speed needle valve to rotate the spraybar so that the slot is centered.
The idle needle can be seen in the slot of the spraybar. It looks like a piece of wire that has the end squarely cutoff. It should be less than one-half way across the slot when the venturi is opened to full.
The high-speed needle should be opened about 2-1/2 to 3 turns out from closed.
All of these settings are very rich. You'll have to start the engine at about 1/4 to1/3 throttle. Once the engine starts, advance the throttle to full. You can then lean the high-speed needle until the engine is running just rich of peak RPM.
Once you have the high-speed needle set, you can retard the throttle a bit and use the idle needle to adjust the engine. Retard a bit, and adjust. Keep doing this until you have reached the desired idle RPM and mixture. Remember, since we started out with an intentionally-rich setting, the idle mixture will have to be leaned.
Finally, the midrange can be adjusted by rotating the spraybar a hair. Just loosen the two screws next to the high-speed needle and rotate the spraybar just a tiny bit. Either direction is OK. This will help you get a good transition and midrange.
We use an O.S. #8 glowplug, although a lot of people have had success with the O.S. Type F glowplug. We recommend you try both to see what works best for you.
Sincerely,
Mrs. AnnMarie Cross
Senior Manager, Proprietary Services and Support
Great Planes Model Distributors
[email protected]
www.greatplanes.com
www.bestrc.com
NO AUTORESPONDER
How much run time does the engine have? How much time do you spend at half throttle in flight?
This is some basic info from our engine techs on the big tigres. Please let me know how this compares to what you've tried:
Once your BIG SuperTigre has a gallon or two of regular fuel run through it, you can use one of the so-called "SuperTigre, or Super-T" fuels, which have 10%-12% oil content. Keep Nitro 10% or lower for best operation.
To properly set up your carburetor, there are a few steps...
Make sure the spraybar is set so that the fuel slot is pointed straight down the center of the carburetor. You will have to look through the carb from the bottom, with the venturi opened to full. Loosen the two screws next to the high-speed needle valve to rotate the spraybar so that the slot is centered.
The idle needle can be seen in the slot of the spraybar. It looks like a piece of wire that has the end squarely cutoff. It should be less than one-half way across the slot when the venturi is opened to full.
The high-speed needle should be opened about 2-1/2 to 3 turns out from closed.
All of these settings are very rich. You'll have to start the engine at about 1/4 to1/3 throttle. Once the engine starts, advance the throttle to full. You can then lean the high-speed needle until the engine is running just rich of peak RPM.
Once you have the high-speed needle set, you can retard the throttle a bit and use the idle needle to adjust the engine. Retard a bit, and adjust. Keep doing this until you have reached the desired idle RPM and mixture. Remember, since we started out with an intentionally-rich setting, the idle mixture will have to be leaned.
Finally, the midrange can be adjusted by rotating the spraybar a hair. Just loosen the two screws next to the high-speed needle and rotate the spraybar just a tiny bit. Either direction is OK. This will help you get a good transition and midrange.
We use an O.S. #8 glowplug, although a lot of people have had success with the O.S. Type F glowplug. We recommend you try both to see what works best for you.
Sincerely,
Mrs. AnnMarie Cross
Senior Manager, Proprietary Services and Support
Great Planes Model Distributors
[email protected]
www.greatplanes.com
www.bestrc.com
NO AUTORESPONDER
04-08-2002, 03:20 PM
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ST 2500
AnnMarie,
Thanks for the advice. I'll work with the carb and change the glowplug. The engine is well broken in and has many hours on it.
Regards,
Thanks for the advice. I'll work with the carb and change the glowplug. The engine is well broken in and has many hours on it.
Regards,
04-08-2002, 03:22 PM
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2500 problems
If she's developed this recently, and the steps above don't help, then she probably is past due for a checkup. Plese send her in for service.
Sincerely,
Mrs. AnnMarie Cross
Senior Manager, Proprietary Services and Support
Great Planes Model Distributors
[email protected]
www.greatplanes.com
www.bestrc.com
NO AUTORESPONDER
Sincerely,
Mrs. AnnMarie Cross
Senior Manager, Proprietary Services and Support
Great Planes Model Distributors
[email protected]
www.greatplanes.com
www.bestrc.com
NO AUTORESPONDER
04-12-2002, 01:28 AM
#6
ST tricks
Here's a trick I learned about ST engines from a guy at our field.
Put an inline fuel filter in the PRESSURE line; between the muffler and the tank.
Seems the ST carbs are very touchy and don't like dirt in the needle. It is possible for soot from the muffler to wind up in the tank, and then eventually into the carb. This is why, sometimes you can crank out, or in on the needle with no apparent engine response. Muffler soot stuck in the needle.
The filter in the pressure line has cured this problem for me.
I own a G90, a 2500, and a 3000. I use this filter in all of them. Works great. Pull it out once in awhile and blow fuel backwards through it too clean. Reassemble and fly away with a big grin on your face.
I need parts for my 3000. Looks like they might be coming down the pipe fairly soon now. I can't wait to get that baby fired up again. It's mounted on a H9 PT-19 1/4 scale. Nice vertical
, but not very scale-like.
Put an inline fuel filter in the PRESSURE line; between the muffler and the tank.
Seems the ST carbs are very touchy and don't like dirt in the needle. It is possible for soot from the muffler to wind up in the tank, and then eventually into the carb. This is why, sometimes you can crank out, or in on the needle with no apparent engine response. Muffler soot stuck in the needle.
The filter in the pressure line has cured this problem for me.
I own a G90, a 2500, and a 3000. I use this filter in all of them. Works great. Pull it out once in awhile and blow fuel backwards through it too clean. Reassemble and fly away with a big grin on your face.
I need parts for my 3000. Looks like they might be coming down the pipe fairly soon now. I can't wait to get that baby fired up again. It's mounted on a H9 PT-19 1/4 scale. Nice vertical
, but not very scale-like.
