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Old 12-15-2014, 04:23 PM   #1
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Default Noob tuning help

I recently got a Savage X 4.6 in a trade and i'm really enjoying this new facet of the hobby (my first nitro.) I've read several guides/videos on how to tune nitro engines but I still have a couple of questions unanswered:

1: When I was tuning my nitro, I came across a phenomenon I didn't see any mention of in any guide I read/saw: After going full throttle and letting offt he gas, the idle would be very low and slowly creep back up. Sometimes the engine would even cut off after letting off the gas. I thought it was too rich but leaning it out only made it worst. I also noticed the idle was very unstable. It got to a point where i decided it was best to reset to factory settings and start from scratch again but I would still like to know what could've caused this.

2: Glow plugs: For some reason I can't understand yet, I keep burning through glow plugs. So far I've burned through 3 in about 6 tanks and can't figure why. My LHS said it probably was because I was letting the tank run dry but my last plug still died even without letting that happen. When i pull them out, they still look almost new. I've included a picture of my last plug.

3: Not really tuning related but my glow plug igniter's battery lasted only about 3 days with a good amount of use (fair bit of starts from tuning.) I was just wondering if this is a normal lifespan for a normal C battery?
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Old 12-15-2014, 05:11 PM   #2
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It could be the clutch or idle gap too small that is lowering the revs after a wot run, If you are blowing plugs you are too lean on the hsn for those plugs, richen it up or try a colder plug that has a thicker wire.
Go over all the exhaust gasket, tank and fuel line also to see if they are all in good shape and sealing, that helps the engine to get good fuel delivery.
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Old 12-16-2014, 07:05 AM   #3
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I noticed yesterday the exhaust gasket is cracked a bit towards the end (the part that goes into the exhaust manifold.) Could this be the reason it was killing glow plugs? I don't think it was running overly lean though...
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Old 12-16-2014, 07:31 AM   #4
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Quote:
Originally Posted by IonicRipper View Post
I recently got a Savage X 4.6 in a trade and i'm really enjoying this new facet of the hobby (my first nitro.) I've read several guides/videos on how to tune nitro engines but I still have a couple of questions unanswered:

1: When I was tuning my nitro, I came across a phenomenon I didn't see any mention of in any guide I read/saw: After going full throttle and letting offt he gas, the idle would be very low and slowly creep back up. Sometimes the engine would even cut off after letting off the gas. I thought it was too rich but leaning it out only made it worst. I also noticed the idle was very unstable. It got to a point where i decided it was best to reset to factory settings and start from scratch again but I would still like to know what could've caused this.

2: Glow plugs: For some reason I can't understand yet, I keep burning through glow plugs. So far I've burned through 3 in about 6 tanks and can't figure why. My LHS said it probably was because I was letting the tank run dry but my last plug still died even without letting that happen. When i pull them out, they still look almost new. I've included a picture of my last plug.

3: Not really tuning related but my glow plug igniter's battery lasted only about 3 days with a good amount of use (fair bit of starts from tuning.) I was just wondering if this is a normal lifespan for a normal C battery?
for point number 1. a low idle then creeping back up after a wide open throttle case is a sign of a LEAN low speed needle. you went the wrong way leaning it more. conversely a high idle then settling down after WOT is a case of the LSN being too rich.

point number 2. the fact you leaned the LSN could have caused this.

point 3. possibly, you sound like your using the glow starter more than a normal racer with having so much engine troubles. a new glow starter is cheap these days, so wouldnt be bad idea to invest in another one.
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Old 12-16-2014, 04:46 PM   #5
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The exhaust gasket was actually more chewed up then I though and was probably not sealing very well. That might be what was messing with my carb settings and killing my plugs. Only time will tell...
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