Thunder Tiger GP 40
05-25-2010, 07:55 PM
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Thunder Tiger GP 40
Please help! I have a new Thunder Tiger 40 GP that runs great at a higher throttle setting but wont idle. As the directions suggested I adjusted the air bleed setting but that just made it so it would'nt stay running at any speed. Any suggestion are appreciated.
05-25-2010, 08:31 PM
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RE: Thunder Tiger GP 40
Hi Jorno: Sounds like you have an air leak, or the carb throttle barrel is not closing all the way. Make sure the spring adjusting screw is backed out just far enough that allows the throttle barrel to rotate to completely close off the carb air intake. If that is ok, then it could be the "O" ring is leaking at the carb to engine case. As for the idle air bleed setting, using a strong flashlight, you should be able to look into the air bleed hole and insure that the idle
needle valve has moved into just half of the hole opening. This is generally the starting point for adjusting the idle mixture to feed the right amount of air to lean out amount incoming fuel for the idle speed you want, and for smooth throttle response going from idle to full throttle. The main engine needle valve needs to be adjusted first before moving to adjust the air bleed needle valve. Get back to me at: [email protected] if you have any more questions. Would like to know if you get the engine to run correctly.
needle valve has moved into just half of the hole opening. This is generally the starting point for adjusting the idle mixture to feed the right amount of air to lean out amount incoming fuel for the idle speed you want, and for smooth throttle response going from idle to full throttle. The main engine needle valve needs to be adjusted first before moving to adjust the air bleed needle valve. Get back to me at: [email protected] if you have any more questions. Would like to know if you get the engine to run correctly.
05-25-2010, 08:34 PM
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RE: Thunder Tiger GP 40
G'day
I am not sure what you meant by "it would stay running at any speed". Do you mean you can't stop it?
I owned a GP 40 about 20 years ago. Mine never idled well, it always spluttered as if it was rich at idle no matter how far I opened the air bleed. A friend had one too and he drilled out the air bleed hole by a very small amount and he said this fixed the problem. I just used to "blip" the throttle to clear the engine and keep it idling that way.
Most engines do not idle well when they are new anyway so if it is very new you may be expecting too much from it. Use a prop with less pitch and set the idle a bit high until it runs in.
Poor idle is also associated with fuel that has absorbed too much water. Is your fuel fresh?
Also, I have been using a new Super Tigre G51 recently and could not get it to idle. Eventually after a couple of weeks of frustration I replaced the original glow plug with an OS F (four stroke) glow plug and the engine was instantly cured of its idle problem. Could your plug be unsuitable? I would start with an OS 8. (I used the F because it was all I had. Most of my engines are four strokes).
You also did not say what prop and what fuel you are using. I would use a fuel with 10% nitro, 20% oil (preferable containing quite a bit of castor oil) and methanol. Plain bearing (bushed) engines like your GP need a certain amount of castor in their fuel. I would use at least a quarter of the oil as castor (5% of total). I have some old Enya plain bearings engines and they like this mixture. They like all castor oil fuel even better.
I am not sure what you meant by "it would stay running at any speed". Do you mean you can't stop it?
I owned a GP 40 about 20 years ago. Mine never idled well, it always spluttered as if it was rich at idle no matter how far I opened the air bleed. A friend had one too and he drilled out the air bleed hole by a very small amount and he said this fixed the problem. I just used to "blip" the throttle to clear the engine and keep it idling that way.
Most engines do not idle well when they are new anyway so if it is very new you may be expecting too much from it. Use a prop with less pitch and set the idle a bit high until it runs in.
Poor idle is also associated with fuel that has absorbed too much water. Is your fuel fresh?
Also, I have been using a new Super Tigre G51 recently and could not get it to idle. Eventually after a couple of weeks of frustration I replaced the original glow plug with an OS F (four stroke) glow plug and the engine was instantly cured of its idle problem. Could your plug be unsuitable? I would start with an OS 8. (I used the F because it was all I had. Most of my engines are four strokes).
You also did not say what prop and what fuel you are using. I would use a fuel with 10% nitro, 20% oil (preferable containing quite a bit of castor oil) and methanol. Plain bearing (bushed) engines like your GP need a certain amount of castor in their fuel. I would use at least a quarter of the oil as castor (5% of total). I have some old Enya plain bearings engines and they like this mixture. They like all castor oil fuel even better.
08-08-2021, 01:32 PM
#6
Dear all
i habe 2 Magnum GP40 left from my stock and I installed them into a new Harmony from ripmax.
i don’t get the engines running well.
therefor I re-installed them to put them on a test bench.
I’m using Graupner 16% Methanol fuel which Is pretty nice on all my other (OS, Rossi and ST) engines.
unfortunately I disassembled them before running as the were stucked for about 10 years in a box.
I assume that I don’t set the Nozzle right.
This is the gap I’m looking to fix:
i habe 2 Magnum GP40 left from my stock and I installed them into a new Harmony from ripmax.
i don’t get the engines running well.
therefor I re-installed them to put them on a test bench.
I’m using Graupner 16% Methanol fuel which Is pretty nice on all my other (OS, Rossi and ST) engines.
unfortunately I disassembled them before running as the were stucked for about 10 years in a box.
I assume that I don’t set the Nozzle right.
This is the gap I’m looking to fix:
