spark plug colour

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mark nichols · 03-07-2009, 01:02 PM

Hi Guys,,

just removed my spark plug from my zdz 40 after 2.5 gallons and its dark black and slightly oily, i re tuned the engine about 20 flights ago am i too rich or is this good. Ive got a good idle and top end transition is good, could be slightly quicker but i do have a 21x8 prop flies fantastic though.

Mark

3Dguy · 03-07-2009, 06:50 PM

I think you're running it a bit rich. This is what you want... Darker is too rich, and lighter is too lean.

Altavillan · 03-07-2009, 08:05 PM

If your spark plug didn't have excessive deposits of carbon and an inspection down the plug hole and exhaust port doesn't reveal excessive carbon or soot deposits, then a dark brown plug isn't necessarily bad. That is if your engine isn't 4 cycling to much or stumbling on throttle advance. To me it sounds like it could be a tad ritch but engines run cooler a tad ritch and should last longer. I try to get my engines to run as wet as possible without 4 cycling straight and level, or building up deposits.

mark nichols · 03-08-2009, 03:29 AM

I think i need a slight tweak on my tuning then, i did a retune as the engine came on song, and its been fine i have noticed the last few flights the advance slowing down slightly, so i guess i must still be too rich.

Nearly getting there.

Mark

pe reivers · 03-08-2009, 05:05 AM

	Quote: Originally Posted by 3Dguy
	I think you're running it a bit rich. This is what you want... Darker is too rich, and lighter is too lean.

That seems to be a picture I once took.
The color is a bit deceiving, because at the time I was testing Aspen alcylate fuel, and the oil brand caused a slightly darker deposit. To check for best mixture settings, one has to look down into the plug, where the isolator meets the body.
I wrote an article on walbro setings an plug reading at http://www.prme.nl/forum/viewtopic.php?t=10 In there also is a nice graph from two-stroke-racing-USA. The best graph I have ever seen.

3Dguy · 03-08-2009, 05:35 AM

	Quote: Originally Posted by pe reivers
	That seems to be a picture I once took. The color is a bit deceiving, because at the time I was testing Aspen alcylate fuel, and the oil brand caused a slightly darker deposit. To check for best mixture settings, one has to look down into the plug, where the isolator meets the body. I wrote an article on walbro setings an plug reading at http://www.prme.nl/forum/viewtopic.php?t=10 In there also is a nice graph from two-stroke-racing-USA. The best graph I have ever seen.

It is.

That article is really good! Now I'm going to tear up some spark plugs.

Sergio Costa · 03-08-2009, 06:14 AM

very good!

mark nichols · 03-08-2009, 08:16 AM

Brilliant Im so glad i posted that article is great,

Many thanks

Mark

mark nichols · 08-01-2009, 08:37 AM

Well this is my plug colour still having a few issues.

Mark

pe reivers · 08-02-2009, 06:14 AM

I do not see any issues with this plug. Run it a bit more, and check again. The fuel and oil used have influence on the color. Some are brown, some are grey. Somewhere between white and black is OK. White is too lean, black is too rich or too cold (if you used a different plug)

N726AC · 08-02-2009, 08:36 AM

I think you misspelled color.

pe reivers · 08-03-2009, 10:21 AM

wikipedia:
Color or colour (see spelling differences) is the visual perceptual property corresponding in humans to the categories called red, yellow, blue and others.

03-07-2009, 01:02 PM	#1
mark nichols Bad-ass Super Contributer! Join Date: Mar 2007 Location: aberdeenshire Posts: 454	spark plug colour Hi Guys,, just removed my spark plug from my zdz 40 after 2.5 gallons and its dark black and slightly oily, i re tuned the engine about 20 flights ago am i too rich or is this good. Ive got a good idle and top end transition is good, could be slightly quicker but i do have a 21x8 prop flies fantastic though. Mark

03-07-2009, 06:50 PM	#2
3Dguy Whatchu lookin at?! Join Date: Jan 2008 Location: Antioch, Tennessee, USA Age: 20 Posts: 14,171	Re: spark plug colour I think you're running it a bit rich. This is what you want... Darker is too rich, and lighter is too lean. __________________ *-Anderson "Sweatshop"*

03-07-2009, 08:05 PM	#3
Altavillan Bad-ass Super Contributer! Join Date: Apr 2007 Location: Altaville, California Posts: 625	Re: spark plug colour If your spark plug didn't have excessive deposits of carbon and an inspection down the plug hole and exhaust port doesn't reveal excessive carbon or soot deposits, then a dark brown plug isn't necessarily bad. That is if your engine isn't 4 cycling to much or stumbling on throttle advance. To me it sounds like it could be a tad ritch but engines run cooler a tad ritch and should last longer. I try to get my engines to run as wet as possible without 4 cycling straight and level, or building up deposits.

03-08-2009, 03:29 AM	#4
mark nichols Bad-ass Super Contributer! Join Date: Mar 2007 Location: aberdeenshire Posts: 454	Re: spark plug colour I think i need a slight tweak on my tuning then, i did a retune as the engine came on song, and its been fine i have noticed the last few flights the advance slowing down slightly, so i guess i must still be too rich. Nearly getting there. Mark

03-08-2009, 06:14 AM	#7
Sergio Costa Sérgio Costa Join Date: Jan 2006 Location: Portugal Age: 39 Posts: 187	Re: spark plug colour very good! __________________ um HOMEM vale pelas atitudes que tem ! nao pelo que demonstra ser !!!!! "The value of a man is not so much found in what he does, but in how he does it" !!! Sergio Costa PORTUGAL

03-08-2009, 08:16 AM	#8
mark nichols Bad-ass Super Contributer! Join Date: Mar 2007 Location: aberdeenshire Posts: 454	Re: spark plug colour Brilliant Im so glad i posted that article is great, Many thanks Mark

08-01-2009, 08:37 AM	#9
mark nichols Bad-ass Super Contributer! Join Date: Mar 2007 Location: aberdeenshire Posts: 454	Re: spark plug colour Well this is my plug colour still having a few issues. Mark Attached Thumbnails 43.5 KB · Views: 36

08-02-2009, 06:14 AM	#10
pe reivers Bad-ass Super Contributer! Join Date: Apr 2007 Location: The netherlands Age: 68 Posts: 1,591	Re: spark plug colour I do not see any issues with this plug. Run it a bit more, and check again. The fuel and oil used have influence on the color. Some are brown, some are grey. Somewhere between white and black is OK. White is too lean, black is too rich or too cold (if you used a different plug) __________________ Best regards, Pe Reivers Dealer for MTW, MVVS, MOKImotor, Mejzlik, Xoar, RCexl www.mvvs.nl www.prme.nl/forum/

08-02-2009, 08:36 AM	#11
N726AC 100LL User Join Date: Sep 2006 Location: Ft Myers Florida Posts: 4,301	Re: spark plug colour I think you misspelled color. __________________ TonyG@RedAeroRC.com

08-03-2009, 10:21 AM	#12
pe reivers Bad-ass Super Contributer! Join Date: Apr 2007 Location: The netherlands Age: 68 Posts: 1,591	Re: spark plug colour wikipedia: Color or colour (see spelling differences) is the visual perceptual property corresponding in humans to the categories called red, yellow, blue and others. __________________ Best regards, Pe Reivers Dealer for MTW, MVVS, MOKImotor, Mejzlik, Xoar, RCexl www.mvvs.nl www.prme.nl/forum/

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