Offshoreonly.com - Read my plugs please

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This is what they should look closer to, I took these out of my engine at the end of this year. Roughly 60 hours run and around 40 hour between 4500 to 5500 and 12:3:1 AF in that RPM range.
https://cimg6.ibsrv.net/gimg/www.off...c06d72c729.jpg
https://cimg7.ibsrv.net/gimg/www.off...e136fa114c.jpg

Sorry I don't know how to resize my pic's lol

Edit figured it out !!!!!!!!!

You can’t idle back and then check the plugs. Stop,get to neutral, and shut down as quickly as you can. The plugs may look different from cylinder to cylinder so you’ll want to check all 8. I take 2 sets of gapped plugs and check one set at 3600 and one at max rpm. Takes a few hours with cool time. If you really are at 14:1 at idle that may be the reason for the chalky electrode. Aluminum specs are shiny under bright light. If you see that it’s no bueno.

To read them accurately you'll need a plug reading light/tool.
https://inductionsolutions.com/shop/...-reading-tool/

Quote:

Originally Posted by Camalot (Post 4664461)

Looks rich to me

Quote:

Originally Posted by underpsi68 (Post 4664512)

Looks rich to me

Yep, way rich.

To the OP, Like was said earlier, plug readings need to be taken with a fresh set of plugs.
Run a 1/2 to mile at WOT and shut down and then read #2 and #7. They are generally the leanest running cylinders.
Next, run another mile at cruise speed around 3800 rpms and shut down and take readings.

Article with pics https://www.dragstuff.com/techarticl...ead-plugs.html

Yeah your right not the best example :) and the engine had been fogged. I was trying to show no aluminium deposit to the electrode lol

That's a nice build and has to make some decent power. Just wondering if you might be having some carb issues. Would be nice to try a 750 dp. I ran a 780 on a 383 of mine and it loved it. AFR's are nice without a doubt but good old fashion plug readings are still crucial in my opinion. This is a good example as to why.

also to note are you using fuel additives ? that changes things as to what shows up on the spark plugs. Actually with the current blend of fuels plug readings really not a true guideline like the past was. I have pulled plugs out that had a full redish hue to them and its part of the fuel add packages form the fuel blenders for the reasons why . Also any blow by will show on spark plugs.

Also no anti seize on the plugs especially for reading them. I already knew this from years past especially with DIS ignitions set ups. NO anti seize period.

I talked to NGK engineers in person as I usually do when I run into them - even just currently -- one guy from Canada and one guy in WI right next to Merc / Mercruiser plants. Here is the reason why not to use anti seize and I reconfirmed exactly what I already knew.

1. the plugs already has a coating on the threads from the plug manu. NGK 4 surely does as I have been told this a 100 times by all NGK employees many years ago.
2. the anti seize changes the hot / cold range ratings of the spark plugs - that is the important issue at hand using it
3. Possible and mostly LIKELY comprising the ground path ---- spark plug to cyc head -
4. False install from tightening the plug into the head especially a false reading using a torque wrench. All the spark plug manu strongly recommend using a torque wrench for the spark plug installs.
5, Too much anti seize will have negative results for spark output 4 sure. They said they have tested that one 100 percent. And causes misfires.

anyways just passing that along again.

watch out when doing wot and then just shutting your engine off. One is water will rush up the exhaust and into the cylinders.

2 is that can be hard on the outdrive / propshaft and gears. Just saying to help prevent other issues and just incase