Starting Zenoah G-38
07-27-2006, 11:16 AM
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Starting Zenoah G-38
I need some advice on starting a gas engine. I have recently acquired an almost new G-38 airplane engine. I wanted to see how well it runs so I set it up on a test stand and put a prop on it. The previous owner says that he started it by flipping the prop, but I can't get it to fire. Is there a trick to it that I am missing or am I wasting my time trying to flip-start the engine? I am getting fuel to the cylinder OK. I pulled the plug and checked for spark, I am seeing a weak spark when I flip the prop as fast as I can by hand. Any suggestions?
07-27-2006, 12:22 PM
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RE: Starting Zenoah G-38
are you choking the engine? i would say choke it flip it about 3 or 4 times until it fires then un-choke and repeat until it starts and runs. magneto engines are a booger to get started by hand. you may look for an electric starter or some guys use a 18v cordless drill with a cone adapter.
07-27-2006, 09:40 PM
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RE: Starting Zenoah G-38
The gap between the coil and mag. should be a business card thick. Make sure no surface rust is on either timing sections. You might spray carb/choke cleaner around the plug ceramic then burn off with a lighter after shaking it dry. Clean the plug gap too.
Open throttle wide and place your thumb over carb and pull prop thru till you get gas on your thumb. DON'T flip prop thru to prime since I didn't read that you have a kill switch hooked up. Don't forget to put the carb butterfly back to just a crack open to flip start.
Open throttle wide and place your thumb over carb and pull prop thru till you get gas on your thumb. DON'T flip prop thru to prime since I didn't read that you have a kill switch hooked up. Don't forget to put the carb butterfly back to just a crack open to flip start.
07-28-2006, 06:29 AM
#4
RE: Starting Zenoah G-38
Also on your G-38 and other Zenoah engines, you can't put the prop up against compression and then flip it expecting it to start.
The magnets are well past the coil at that position and you get no spark.
You have to set the prop on the shaft so that compression is at 11 o'clock. Move the blade back to about 3 o'clock and firmly flip the prop through 180 degrees.
It takes some doing, but it can be done.
The magnets are well past the coil at that position and you get no spark.
You have to set the prop on the shaft so that compression is at 11 o'clock. Move the blade back to about 3 o'clock and firmly flip the prop through 180 degrees.
It takes some doing, but it can be done.
07-28-2006, 12:42 PM
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RE: Starting Zenoah G-38
Just for the record, I am getting gas to the carb by choking it as you have suggested. I'll check the gap on the magneto and the plug. Thanks for all the advice. Hopefully I can get it to run.
One other question, there is a wire coming off the magneto, that looks like it needs to be grounded, not sure. The manual doesn't say anything about it. It has a male bullet connector. I ohmed it out, and it is at ground potential.
One other question, there is a wire coming off the magneto, that looks like it needs to be grounded, not sure. The manual doesn't say anything about it. It has a male bullet connector. I ohmed it out, and it is at ground potential.
07-28-2006, 01:34 PM
#7
RE: Starting Zenoah G-38
Flyman49,
We have a bunch of Zenoah's of various sizes at our field and this is the procedures that we use to start them.
1. first of all, the wire you mentioned. This is the ignition kill. As said above, when grounded the motor won't run. Connect this wire to a toggle switch to use as an engine kill switch. Also, leave it closed whenever you are working on the engine to ensure that the motor won't accidentally fire and run.
2. Now you'll need to find where the magnets on the flywheel are in relation to the magneto. Ideally you should have the magnets just before the magneto when the prop is approximately in the 3 o'clock position. You want it before the magneto when you get ready to flip it.
3. Ensure the tank has fuel in it.
4. Close the choke and put the throttle at the idle setting.
5. Now it's time to throw the prop. I prefer to say "throw" because that's more of the motion you will have. Before you touch the prop make sure you have a heavy leather glove on your hand, I prefer to use a welders glove because it's plenty thick enough to protect your hand in case the prop kicks back. How grab the prop at the 3 o'clock position and "throw" it counter-clockwise, moving your hand in a circular motion. The trick is to take the prop over the top 12 o'clock position and then as the prop move downward let you hand come out of the arc of the prop as it moves on the downward side of the "throw". This gets your hand out of the way if the engine fires.
6. Before reaching for the prop to throw it again make sure the prop has come to a complete stop.
7. Continue to throw the prop until the motor fires. It more than likely isn't going to start, but you will hear it fire.
8. Take the choke off.
9. Now continue to throw the prop until the motor starts.
Now, with all that said and done, I would recommend getting a spring starter from [link=http://www.bennettbuilt.com]B & B specialties[/link]. This lets you wind the prop backwards agains a spring and then all you have to do is simply let go of the prop to get it started. It's a lot easier on the arm this way. I have a G-38 myself and this is what I have on mine.
Hope this helps
Ken
We have a bunch of Zenoah's of various sizes at our field and this is the procedures that we use to start them.
1. first of all, the wire you mentioned. This is the ignition kill. As said above, when grounded the motor won't run. Connect this wire to a toggle switch to use as an engine kill switch. Also, leave it closed whenever you are working on the engine to ensure that the motor won't accidentally fire and run.
2. Now you'll need to find where the magnets on the flywheel are in relation to the magneto. Ideally you should have the magnets just before the magneto when the prop is approximately in the 3 o'clock position. You want it before the magneto when you get ready to flip it.
3. Ensure the tank has fuel in it.
4. Close the choke and put the throttle at the idle setting.
5. Now it's time to throw the prop. I prefer to say "throw" because that's more of the motion you will have. Before you touch the prop make sure you have a heavy leather glove on your hand, I prefer to use a welders glove because it's plenty thick enough to protect your hand in case the prop kicks back. How grab the prop at the 3 o'clock position and "throw" it counter-clockwise, moving your hand in a circular motion. The trick is to take the prop over the top 12 o'clock position and then as the prop move downward let you hand come out of the arc of the prop as it moves on the downward side of the "throw". This gets your hand out of the way if the engine fires.
6. Before reaching for the prop to throw it again make sure the prop has come to a complete stop.
7. Continue to throw the prop until the motor fires. It more than likely isn't going to start, but you will hear it fire.
8. Take the choke off.
9. Now continue to throw the prop until the motor starts.
Now, with all that said and done, I would recommend getting a spring starter from [link=http://www.bennettbuilt.com]B & B specialties[/link]. This lets you wind the prop backwards agains a spring and then all you have to do is simply let go of the prop to get it started. It's a lot easier on the arm this way. I have a G-38 myself and this is what I have on mine.
Hope this helps
Ken
08-19-2010, 01:52 PM
#8
RE: Starting Zenoah G-38
After you get the G38 Zenoah broke in a fair amout & tunned the way it should be, you will not need that spring start at all. I took my spring start off to save weight. I have had guys say they never seen a flywheel mag G38 Idle thatslow. It is a good engine...just kinda heavy! Capt,n
