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Old 04-13-2009, 05:30 AM
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Default Which plug?

What is the golden rule for which plugs to use with 20% fuel?

Are there any charts that will help explain?

cold plugs for cold weather
hot plugs for hot weather
mediums for ?
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Old 04-13-2009, 05:39 AM
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There is no Golden Rule or PERFECT SETUP. It varies by regional air temp/humidity ratings. The higher the humidity level is in your region, the colder the plug you will want to run.

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Old 04-13-2009, 07:16 AM
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is nova C6TF = RB #6 ?
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Old 04-13-2009, 07:23 AM
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If you're on 20% fuel you are also safer with hotter plugs. If your engine takes a standard plug get some McCoy MC-8 (medium) and MC-59 (hot) and you should be covered.
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Old 04-13-2009, 09:42 AM
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What can I do to maintain a consistent idle for more than 15 seconds? Ive tried every single needle adjustment...nothing. Right now I have ODonnell Medium Sport Plugs and when I finish with them (2 left) I want to try something else. I will be running Byron's 30% Pro Driver in the Mach 427. Ive heard soem people say to run cold plugs and 30% on this engine in previous threads, but I want to get a second opinion. Which plugs will be better for idling/durability? And what is the difference between the ODonnell sport and say the #99 cold plug?
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Old 04-13-2009, 11:06 AM
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you possibly might have an air leak. check the carb for any leaks. I've heard people squirting water at the engine while it's running to see if there is any bubbling, indicating an air leak.
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Old 04-13-2009, 11:27 AM
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If the engine is in good condition then it's likely that you have too large an idle gap compensated for by a too-rich LSN setting.
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Old 04-13-2009, 11:34 AM
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Originally Posted by gnpower
you possibly might have an air leak. check the carb for any leaks. I've heard people squirting water at the engine while it's running to see if there is any bubbling, indicating an air leak.
There is no air leak. Ive had an engine that had an air leak and it is nothing liek that. This enigne starts up 1st time cold and is too powerful for a buggy running at 205f.

Originally Posted by Davidka
If the engine is in good condition then it's likely that you have too large an idle gap compensated for by a too-rich LSN setting.
Idle gap is fine. Actually someone told me that I had TOO lean of a lsn, then I burnt 2 glow plugs. Another told me I had a too rich lsn and too lean hsn. For the pinch test, engine revs up really high indicating it needs to be leaner on the lsn. So if it doesnt idle for 15 seconds...what could be the problem? Someone told me that I have a small leak in my exhaust/header gasket (going to get a new one) as there was a little bit of blue smoke coming out from it. Could that be the idle problem?
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Old 04-13-2009, 12:10 PM
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If you burnt plugs then you are too lean somewhere, more likely the top end since the engine won't idle all that long. A small exhaust gasket leak will make a mess but won't have a huge effect on the way the engine runs.

Try running it up to temp then let it idle down. When it dies, take out the plug and check if it's wet (rich) or dry/gray (lean). I still think it's too rich on the bottom because an engine tuned that way will otherwise run fine, just won't idle very long.
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Old 04-13-2009, 12:12 PM
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Originally Posted by Chris__RC
For the pinch test, engine revs up really high indicating it needs to be leaner on the lsn. So if it doesnt idle for 15 seconds...what could be the problem?
Judging by the above symptoms, it does sound like your lsn is too rich. This would cause the engine to "load up" with fuel and die after idling for a while. I would lean the lsn in very small increments. After each adjustment, run the engine at wot for a couple of times and then do the pinch test again.
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Old 04-13-2009, 12:36 PM
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Originally Posted by Davidka
If you burnt plugs then you are too lean somewhere, more likely the top end since the engine won't idle all that long. A small exhaust gasket leak will make a mess but won't have a huge effect on the way the engine runs.

Try running it up to temp then let it idle down. When it dies, take out the plug and check if it's wet (rich) or dry/gray (lean). I still think it's too rich on the bottom because an engine tuned that way will otherwise run fine, just won't idle very long.
Well, I wont be able to run it for another 2 weeks (preparing for a big race). Like I said before, the track owner was tuning my engine and he had to richen the lsn over a turn, as it was bogging in which I thought a rich bog, but it was a lean bog. Even then, engine wouldnt idle very long. He richened it up, amazing low end throttle response. I asked him about idling, and he told me about teh gasket and engines werent made to idle that long. When i took out one of the 2 burnt plugs, the wire was white. He helped me tune it again and it didnt happen in the last 10 tanks though.

Originally Posted by Rampokker
Judging by the above symptoms, it does sound like your lsn is too rich. This would cause the engine to "load up" with fuel and die after idling for a while. I would lean the lsn in very small increments. After each adjustment, run the engine at wot for a couple of times and then do the pinch test again.
Read above^^^. But like I said, throttle response was amazing, I need to actually get carbon shoes/softer springs because it feels likea new engine! I will do that......in 2 weeks.
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