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Old 09-23-2019, 09:19 AM
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Help!
Evolution 62GX Rich running

Hi, I have an Evo 62GX which requires a rich mixture in order to be able to open the throttle briskly without out it dying. This means that the engine is burbling all the way from idle to 3/4 throttle at which point it sounds like a nice 2 stroke. I have serviced the carb but the problem persists. Anybody got any ideas before I loose the rest of my hair. Fuel mix is 32:1. A new plug (gap 0.20) has been fitted. This engine has good compression and starts easily by hand.
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Last edited by Derekg; 09-23-2019 at 12:00 PM.
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Old 09-23-2019, 10:34 AM
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Have you check the timing.I have one of these engines and it was retarded from factory.I have to admit that it's down in power compared to other 60's.It may just need a pipe to get any performance out of it ,like the 58 was.Other than that mine runs fine,just a dog though.

One more thought what prop are you running.Mine won't spin a 24-8,just a 23-8 Xoar and it is only at 6950rpm's.So a 24-8 won't have good throttle response.
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Old 09-23-2019, 01:12 PM
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Low needs leaned out or not enough prop. It's very hard to get all the burble out.
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Old 09-23-2019, 01:23 PM
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If I lean out the low you cannot throttle up quickly without it dying. Prop is 23x8 Xoar.
To Closetguy: what do you mean "just a dog though"?
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Old 09-23-2019, 01:57 PM
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I have the same engine and it does the same thing. this engine was originally designed to be EFI but Horizon gave up. It was then adapted to a conventional carb. I seized mine last year when it was tuned "properly" so since then I run it a bit blurbly and it cleans up in the air. I run a 23/10. the bottom end transition will get better with time. I have one on a H9 Mustang and a friend has one in a 91 inch Extra 300.
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Old 09-23-2019, 02:10 PM
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Quote:
Originally Posted by Derekg View Post
If I lean out the low you cannot throttle up quickly without it dying. Prop is 23x8 Xoar.
To Closetguy: what do you mean "just a dog though"?
The way these carbs work you will lean the low then have too richen the high to compensate. I can have a engine tuned this way in 5 minutes. It's harder to explain then it is to do

https://www.flyinggiants.com/forums/...read.php?t=427
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Old 09-23-2019, 02:33 PM
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Quote:
Originally Posted by Derekg View Post
If I lean out the low you cannot throttle up quickly without it dying. Prop is 23x8 Xoar.
To Closetguy: what do you mean "just a dog though"?
I am just being sarcastic about the power.I have two DLE55's and they turn the same prop at the same rpm.Most any 60 will get 7000 or just a bit better on a Falcon 24-8.Thats my only complaint about the engine,other than that it runs great.No midrange burble good transition,but it should spinning a 23-8,that's not much of a loading prop for a 62.This engine could be a total different animal on a pipe,just like the 58 was.It's a carbon copy of the 58 in terms of the ports, piston and crank design.But I'm not into pipes any longer and don't want to fool with it.
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Old 09-26-2019, 02:31 AM
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Thank you all for your help so far, but nothing has changed with the engine. Here is my question to hopefully get to the root of the problem. Why does my engine HAVE to run rich in order to transition smoothly from idle to full revs?
There is no way if you lean it out that it will go from idle to full throttle without dying.
Are all Evolution 62,s like this?
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Old 09-26-2019, 08:55 AM
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I would look at the carb next,as long as you know the timing is correct,28*-30* BTDC.
I have no knowledge about the Walbro HDA 336 that comes on the 62.Try a rebuild kit in the carb,or just try a Walbro HDA 246A.That carb comes on most of the 60's today and I know it to work well.Mine has no issues like yours,but I do have a rcexl ignition on it.Just because it was already mounted in the plane from the engine before.
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Old 09-27-2019, 05:35 PM
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I have ordered a HDA246 carb, let's see if that makes a difference. Will keep you updated.
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Old 10-13-2019, 10:53 AM
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Carb cured all the problems, thanks to everybody who assisted me.
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Old Yesterday, 04:40 AM
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I know the original carb was bad.But can you tell if the top end is better,any rpm increase.
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