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G-62 quit running

Old 09-05-2005, 09:55 PM
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aghost
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Default G-62 quit running

After eighteen flights, I did a three point landing with my TF P-51 (nose and main gear, did not break the prop). Its been two months since then and I have only been able to start the engine once. The engine is a plain G-62 with Walbro carb. Prior to my three pointer, I was able to hand start it with a couple of flips. Now it seems to fire a couple of times, then quits. The one time it ran, it seemed OK.

I have read lots of G-xx threads, changed fuel, plug, carb gaskets, pulled the fuel tank, checked the fuel lines, etc. It has a spark and fuel, so I keep thinking there is something wrong in the carb. I am going to take it apart again. Is there something else I should be looking for?


Brian
Old 09-05-2005, 11:49 PM
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rcdude7
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Default RE: G-62 quit running

Did you check the gap between the source coil and the rotor. If the impact caused it to open some that might explain the hard starting. My zenoah owners manual spec for the gap is 0.010-0.014"

Mike
Old 09-05-2005, 11:50 PM
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Default RE: G-62 quit running

I had a similar problem, as it turned out the disk for the throttle was loose. A new 4-40 cap screw and red locktite fixed my problem.

I am sure Ralph will jump in here and steer you in the right direction..

Good luck

Garry
Old 09-05-2005, 11:53 PM
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Default RE: G-62 quit running

I had a similar problem, as it turned out the disk for the throttle was loose. A new 4-40 cap screw and red locktite fixed my problem.

I am sure Ralph will jump in here and steer you in the right direction..

Good luck

Garry
Old 09-06-2005, 01:30 AM
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Default RE: G-62 quit running

One possibility, once in a while the mag rotor gets loose and shears the key, changing the timing..You can take the two 6mm bolts out and check the nut that holds the rotor on the shaft...With the piston at TDC the first magnet in the rotor will be all the way past the coil and the other will be centered under it...
Check the top screw holding the spark coil on, it's the ground and if loose you'll get intermittent spark, and check the red wire at the plug in connection to the coil...
Maybe a leak in the block under the carb ?
Old 09-06-2005, 07:03 AM
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Default RE: G-62 quit running

Thanks for the suggestions. The air gap is right at .010" so that ought to be OK.
RCIGN1- I did not know quite how to check the timing. Thanks for the instructions.

Brian
Old 09-06-2005, 10:29 AM
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Default RE: G-62 quit running

OOPS..Just checked again...The mag rotor has 3 magnets...When the engine is at TDC the distance from the third magnet in the rotor is vey close to .230 from the left edge of the source coil....[8D]
Old 09-06-2005, 09:54 PM
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Default RE: G-62 quit running

RCIGN1: Thanks for the update. I thought the G-62 did have three magnets, but I did not have time to check it this AM. I have not checked the timing yet, but I will get to it this week.

thanks again,
Brian
Old 09-08-2005, 06:39 PM
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Default RE: G-62 quit running

RCIGN1: Looks like its a timing problem. Attached is a sketch of the magnets and coil at TDC. Let me know if you agree.
The sketch shows the engine upside down as it sits in my plane.

thanks, Brian
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Old 09-08-2005, 09:03 PM
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Default RE: G-62 quit running

I have 3 G-62's and have seen this once in a while. I am using one in a Wild Hare Ultimate and I hand start it. I set the prop at the 1 o'clock position coming on compression and get as fast a run on the prop as possible during starting. I also choke until it pops a couple of times and start at IDLE. (choke at idle)
One last thing, check the screen in the carb for dirt.
Old 09-08-2005, 10:01 PM
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Default RE: G-62 quit running

Looks like yours is OK, the leading edge of the left hand magnet should be about .230 from the bottom leg of the source coil...
Old 09-11-2005, 02:00 PM
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Default RE: G-62 quit running

Since the timing looks OK, I started checking through the fuel system from the tank to carb to the engine again. This time I found a hairline crack in the brown block along the pressure pulse routing. The crack is in the thin part of the web and probably allows a portion of the pressure pulse out into the carb bolt area. I really had to clean all the gasket material residue off the block to find the crack, but it becomes obvious then.

I don't know if this is the problem, but a new brown block is next on my list.

Brian
Old 10-01-2005, 07:58 AM
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Default RE: G-62 quit running

I replaced the insulator block and the carburator. The engine still does not run. I prime it and it will fire once on each of the next four or five flips. Prime it again, and the same results. I set the HS needle valve at various positions from 1 to 2 turns open.

I did make sure the pressure port was open into the cylinder.

Any suggestions are welcome.
Old 02-05-2006, 10:17 AM
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Default RE: G-62 quit running

I put a CH Ignition Jump Start on the engine. It starts right up now. Seems like the engine is breaking in, compression increasing, and I can no longer flip it fast enough to start it.


Brian
Old 02-05-2006, 10:43 AM
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Default RE: G-62 quit running

I would give the engine a shot of gas through the spark plug and flip it to see if it can run out the prime. If it runs out the prime it would be a gas problem and if it only fires once or twice or just pops it's a ignition problem. At least it should put your mind to rest that you are looking in the right direction. Bill
Old 02-05-2006, 10:51 AM
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Default RE: G-62 quit running

The engine is toast, will never run again [:@] Dont waste your time on it.... I need some parts though, send it to me and I will give you 20 bucks for it

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