thunder tiger gp 42
10-26-2009, 06:50 PM
#1
Member
Thread Starter
My Feedback: (1)
Join Date: Oct 2009
Location: wimauma, FL
Posts: 37
Likes: 0
Received 0 Likes
on
0 Posts
thunder tiger gp 42
does anyone know what the screws are on this motor.motor was only ran one time then I got the plane I started it I think its to reach it wont stay running without leaving glow heater attatched.I would like to know the screws and the settings for them and then how to dial it in as I break in.
thanks chet from fl
thanks chet from fl
10-26-2009, 08:21 PM
#2
RE: thunder tiger gp 42
10-26-2009, 08:55 PM
#3
Member
Thread Starter
My Feedback: (1)
Join Date: Oct 2009
Location: wimauma, FL
Posts: 37
Likes: 0
Received 0 Likes
on
0 Posts
RE: thunder tiger gp 42
yes yes yes ,Thank you lnewqban you are the man! Im bran new and now I will print this out and get this motor start tomarrow.today was first day running motor but would only run with glow starter attached thats why I want to know what each screw is and good start settings and then dial in tricks
again thanks
chet from fl
again thanks
chet from fl
10-26-2009, 09:22 PM
#4
RE: thunder tiger gp 42
You are welcome.
You may need to replace the glow plug, which goes bad after some time of use.
When an engine stops after the glow starter is retired, is normally because the glow plug is bad.
Be very careful with the propeller.
Regards!
You may need to replace the glow plug, which goes bad after some time of use.
When an engine stops after the glow starter is retired, is normally because the glow plug is bad.
Be very careful with the propeller.
Regards!
10-26-2009, 10:23 PM
#6
10-27-2009, 12:03 AM
#7
My Feedback: (2)
Join Date: Jun 2005
Location: Omaha, NE
Posts: 4,109
Likes: 0
Received 0 Likes
on
0 Posts
RE: thunder tiger gp 42
I just got done breaking in a new GP-42 on my Thunder Tiger Pitts 40 ARF. The engine had a very tight pinch and I had a hard time getting it to run at less than 3/4 throttle for the first tank or so.
My best advice is to simply turn out the high speed needle about four turns and start your GP-42. It should be sloppy rich, but running fine with the glow ignitor on it. Once it's started, begin turning the high speed needle in (clockwise) one-eighth of a turn at a time until you find the peak needle setting, then richen it back up (counter clockwise) one quarter of a turn. Once you've set the high speed needle to 1/4 turn rich of peak, you can remove the glow ignitor. Finish running one tank of fuel through the engine at wide open throttle while alternating the high speed needle from 1/4 turn rich of peak to 1/2 rich of peak every 15 seconds.
Alternating the needle from 1/4 turn rich of peak to 1/2 turn rich of peak will help the engine stay cool during the initial break-in tank, yet it will be running fast enough that the "pinch" of the new liner and piston won't be so tight as to stop it. One full tank of fuel on the ground should be enough to allow the piston and liner to seat together. The engine will still have a nice snug "pinch" when turning it over by hand, but after one tank the engine should idle and transition without stopping.
It's a bad idea to try to "dial in" the high speed needle before starting the engine. Don't even get close to where you think it should be before firing up the engine for the first time. You want the high speed needle to be at least one to two full turns out and very rich when the engine is first started. You can then work your way in from a very rich needle setting quickly and smoothly without ever risking getting the engine too lean. If you start with the high speed needle even a little too lean when first firing up a new engine, you can instantly damage a brand new engine.
After one tank of fuel through the new GP-42 at full throttle while regularly richening from and then resetting the needle one quarter turn rich of peak, you can test the idle setting. My GP-42 air bleed screw was set perfectly from the factory when checked with the pinch test. With the engine running at it's lowest stable idle throttle setting, pinch the fuel line running to the carburetor:
A) If the engine runs and runs for 8 or 10 seconds before it finally revs up and then quits, you're too rich. Turn out the air bleed screw (counter clockwise) a bit to lean the low end and test again.
B) If the engine quits almost right away without revving up first, your low end is too lean. Turn in the air bleed screw (clockwise) a bit to richen the low end and test again.
C) If the engine starts to rev up a little bit then starts to quit within 2 or 3 seconds after the pinch, it's set just about perfectly. Go fly and have fun.
In summary, when starting a new 2-stroke ABC engine for the first time, start really rich and work your way in to find the peak rpm setting then back up a quarter turn rich. Run the engine at wide open throttle for one tank of fuel. Alternate the high speed needle from 1/4 turn rich of peak to 1/2 turn rich of peak every 15 seconds or so; this will keep the engine cool while the piston and liner seat. Only after you dial in the high speed needle and run a tank of fuel through the engine at wide open throttle, check your idle setting by pinching the carburetor line as previosly described. Once you have a steady reliable idle set and the engine transitions smoothly and quickly from idle to full throttle, you're ready to fly.
My best advice is to simply turn out the high speed needle about four turns and start your GP-42. It should be sloppy rich, but running fine with the glow ignitor on it. Once it's started, begin turning the high speed needle in (clockwise) one-eighth of a turn at a time until you find the peak needle setting, then richen it back up (counter clockwise) one quarter of a turn. Once you've set the high speed needle to 1/4 turn rich of peak, you can remove the glow ignitor. Finish running one tank of fuel through the engine at wide open throttle while alternating the high speed needle from 1/4 turn rich of peak to 1/2 rich of peak every 15 seconds.
Alternating the needle from 1/4 turn rich of peak to 1/2 turn rich of peak will help the engine stay cool during the initial break-in tank, yet it will be running fast enough that the "pinch" of the new liner and piston won't be so tight as to stop it. One full tank of fuel on the ground should be enough to allow the piston and liner to seat together. The engine will still have a nice snug "pinch" when turning it over by hand, but after one tank the engine should idle and transition without stopping.
It's a bad idea to try to "dial in" the high speed needle before starting the engine. Don't even get close to where you think it should be before firing up the engine for the first time. You want the high speed needle to be at least one to two full turns out and very rich when the engine is first started. You can then work your way in from a very rich needle setting quickly and smoothly without ever risking getting the engine too lean. If you start with the high speed needle even a little too lean when first firing up a new engine, you can instantly damage a brand new engine.
After one tank of fuel through the new GP-42 at full throttle while regularly richening from and then resetting the needle one quarter turn rich of peak, you can test the idle setting. My GP-42 air bleed screw was set perfectly from the factory when checked with the pinch test. With the engine running at it's lowest stable idle throttle setting, pinch the fuel line running to the carburetor:
A) If the engine runs and runs for 8 or 10 seconds before it finally revs up and then quits, you're too rich. Turn out the air bleed screw (counter clockwise) a bit to lean the low end and test again.
B) If the engine quits almost right away without revving up first, your low end is too lean. Turn in the air bleed screw (clockwise) a bit to richen the low end and test again.
C) If the engine starts to rev up a little bit then starts to quit within 2 or 3 seconds after the pinch, it's set just about perfectly. Go fly and have fun.
In summary, when starting a new 2-stroke ABC engine for the first time, start really rich and work your way in to find the peak rpm setting then back up a quarter turn rich. Run the engine at wide open throttle for one tank of fuel. Alternate the high speed needle from 1/4 turn rich of peak to 1/2 turn rich of peak every 15 seconds or so; this will keep the engine cool while the piston and liner seat. Only after you dial in the high speed needle and run a tank of fuel through the engine at wide open throttle, check your idle setting by pinching the carburetor line as previosly described. Once you have a steady reliable idle set and the engine transitions smoothly and quickly from idle to full throttle, you're ready to fly.
