Reading plugs
#1
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Joined: Aug 2021
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From: St. Louis, MO
Swapped out the 1050 88 sq jets and had ProSystems put another 1050 together with 78's square. Had the boat out a couple weeks back and ran it pretty hard, but had some idle time getting back to the dock/trailer. I understand that will change the reading vs WOT, but more curious how the plugs look overall? From what I can see, I think they look pretty good. Previously, the plugs were black/wet very rich. 3/5 look a little richer than the rest (still dry), but nothing too horrible to my untrained eye.
Last edited by 540Fever; 05-28-2023 at 11:57 AM. Reason: Correct link to pictures.
#4
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Joined: Mar 2020
Posts: 372
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From: East Tennesseee

Only thing that would show signs of how detonation would be a cracked porcelain.
If you want you know the condition at WOT or Cruise you need to run at that speed for a few minutes and then shut it down and read them. Once you've idled for a few minutes the coloring has completely changed.
#5
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Joined: Mar 2020
Posts: 372
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From: East Tennesseee

Only thing that would show signs of how detonation would be a cracked porcelain.
If you want you know the condition at WOT or Cruise you need to run at that speed for a few minutes and then shut it down and read them. Once you've idled for a few minutes the coloring has completely changed.
If your plugs were wet you need to straighten out the idle adjustment. If the plugs are wet the walls are wet and your killing the rings because it's washing the oil away. The idle adjustment is easy and must be done after fully warming the motor up.
#7
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Joined: Oct 2012
Posts: 2,227
Likes: 531
This
You will see small specs of silver or black. If you cracked a plug, you have severe detonation.
Invest in a cheap otoscope.
A good video on reading plugs.
You will see small specs of silver or black. If you cracked a plug, you have severe detonation.
Invest in a cheap otoscope.
A good video on reading plugs.
Last edited by underpsi68; 05-28-2023 at 07:44 PM.




