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Convince me to change my spark plugs every.....

Old 06-13-2019, 06:05 AM
  #21  
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Two comments that i have read on this forum. First NGK plugs have a coating or plating on them and anti-seize is not recommended. And secondly spark plugs have a crush washer on them and after reinstalling a previously crushed crush washer I have heard that no longer properly seals. That one seems a little far fetched to me. That's why when I take mine out at 300 hrs. I just replace em.
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Old 06-13-2019, 06:12 AM
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Not a big deal either way. The are only about $2.50 each and can literally be changed in 15 minutes.
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Old 06-13-2019, 06:25 AM
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Originally Posted by tarpononecharter View Post
First NGK plugs have a coating or plating on them and anti-seize is not recommended. .
well, NGK says 'the issue' is

"Applying anti-seize to the threads of spark plugs that have a metal plating allows the installer to mistakenly over-tighten the spark plug"

and so the 'solution' is

"simply do not use anti-seize on initial Installation"

But they also explain

"NGK Spark Plugs are manufactured with a special trivalent Zinc-chromate shell plating ...
shell plating acts as a “lubricant” which breaks away from the main body of the spark plug during removal,
preventing damage to the spark plug and or threads in the cylinder head
"

Link:
NGK Tech Bulletin

My own takeaway - use anti-sieze - absolutely if re-installing NGK plugs

but don't be a clueless ape and "mistakenly overtighten"...



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Old 06-13-2019, 06:40 AM
  #24  
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Originally Posted by homeby51 View Post
That's a good point, IMO. Maybe I need to break them free and lube the threads every year? Also, that's the reason I change my water pump impeller....so my drive shaft don't stick to my power head. I realize I don't have to change my impeller, but I do it anyway even though it looks new when I throw it away.
yep, just do it right.

Manufacturers are great in protecting their asses with all those cautions. Plus they are in bussiness of selling plugs.

We ought to protect ours, at the end we are one to run those dogs 10 years in harsh, corrosive enviroment.
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Old 06-13-2019, 06:48 AM
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Originally Posted by Fwpratt View Post
well, NGK says 'the issue' is

"Applying anti-seize to the threads of spark plugs that have a metal plating allows the installer to mistakenly over-tighten the spark plug"

and so the 'solution' is

"simply do not use anti-seize on initial Installation"

But they also explain

"NGK Spark Plugs are manufactured with a special trivalent Zinc-chromate shell plating ...
shell plating acts as a “lubricant” which breaks away from the main body of the spark plug during removal,
preventing damage to the spark plug and or threads in the cylinder head
"

Link:
NGK Tech Bulletin

My own takeaway - use anti-sieze - absolutely if re-installing NGK plugs

but don't be a clueless ape and "mistakenly overtighten"...
Interesting and I thought they didn't want anti-seize because of O2 sensor contamination.
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Old 06-13-2019, 06:18 PM
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Why would you replace this plug? (1500 hours)
Only guilt I suppose

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Old 06-14-2019, 05:32 AM
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Originally Posted by gfretwell View Post
Why would you replace this plug? (1500 hours)
Only guilt I suppose

Attachment 1100832
Very worn electrodes. It's not just the gap, its the shape of the electrodes. The sharper edges, which allow the spark to initiate easier, are all worn down on that plug.
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Old 06-14-2019, 05:45 AM
  #28  
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Originally Posted by tarpononecharter View Post
Belt? Are you referring to your timing belt? Hopefully you are not changing that every 300 hours.
the timing belt needs to be changed periodically, over time it stretches and then can jump timing, then you will be rebuilding the head!
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Old 06-14-2019, 06:05 AM
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I used to pull them every year to inspect but finally got tired of looking at perfectly good plugs. Now I just replace them 300hrs / 3years, whichever comes first. There is also the small chance of cross threading the plugs which obviously increases with the amount of times you mess with them. Don't need that headache.
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Old 06-14-2019, 06:09 AM
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Over 1000 hours on my plugs. Going to change them soon. 3400 hours total.
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Old 06-14-2019, 06:18 AM
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Originally Posted by Rolandt03 View Post
the timing belt needs to be changed periodically, over time it stretches and then can jump timing,

not according to the Gates Rubber Company - who know a bit about belts -

"synchronous belts do not stretch"

Gf000284.pdf
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Old 06-14-2019, 06:22 AM
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Keep in mind that many 4-strokes use a "wasted spark" ignition system where even on the exhaust stroke the plug makes a spark, that simplifies and lowers the cost and complexity of the design.

As a rule of thumb, at about 200 hours. in a 4-stroke you can see the center electrode becoming eroded even though it is still firing. The rounding off of the electrode increases the voltage required to fire and eventually starts to stress the coils and related parts up to the point of misfiring or breaking down the insulation.. Precious metal plugs last longer than conventional ones but do cost quite a bit more.

Conventional plugs in a conventional 4-stroke should usually be changed out at the 200 hour point for best results or follow your manufacturer's guidelines.
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Old 06-14-2019, 06:29 AM
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More important to me would be the removal before they have a chance to corrode/fuse/rust/insert suitable descriptive here to the heads.

For a few bucks a season it’s far cheaper than dealing with headaches of stuck plugs later.
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Old 06-14-2019, 06:38 AM
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Originally Posted by Tainui View Post
More important to me would be the removal before they have a chance to corrode/fuse/rust/insert suitable descriptive here to the heads.

For a few bucks a season it’s far cheaper than dealing with headaches of stuck plugs later.

Most 4-strokes require annual or 100 hour service. At that time plugs are to be inspected and they are removed anyway for either compression or leak-down tests.
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Old 06-14-2019, 06:55 AM
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Originally Posted by Fwpratt View Post
not according to the Gates Rubber Company - who know a bit about belts -

"synchronous belts do not stretch"

Attachment 1100842
i would say maybe not all belts are created equal? all i know is we had a timing belt become loose, causing the motor to jump timing and when it did it bent all the intake valves resulting in a rebuilt head!
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Old 06-14-2019, 07:07 AM
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Originally Posted by Toothpick 10 View Post
Not a big deal either way. The are only about $2.50 each and can literally be changed in 15 minutes.
Not sure about that...I bought a used Maverick flats boat a week ago. Granted it's a 2-stroke, but the plugs were $8/ea.
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Old 06-14-2019, 08:16 AM
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Originally Posted by seahorse View Post
Most 4-strokes require annual or 100 hour service. At that time plugs are to be inspected and they are removed anyway for either compression or leak-down tests.
Why would I do a compression/leak test on a perfectly good running motor every 100 hrs? I could see if there were problems.....
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Old 06-14-2019, 08:50 AM
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Originally Posted by Rolandt03 View Post
the timing belt needs to be changed periodically, over time it stretches and then can jump timing, then you will be rebuilding the head!
Yamaha recommends replacing timing belts every 1,000 hours. I changed mine @ 1,000 hrs. and the old ones looked perfect. Probably wise to check em every 100 hrs. When I considered new motors the lack of a timing belt on Suzuki sounded appealing.
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Old 06-14-2019, 09:11 AM
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Why would you think a slightly worn electrode would actually do anything to performance? A lot of these myths came from the days when we had fairly low energy ignition systems and leaded gas. The high energy systems will work with plugs that might not have worked in your 54 chevy.
They have plug changes up around 100,000 miles in cars these days.
If you are noticing a loss of fuel efficiency or performance issues, throwing a set of plugs at it might be worth the money but screwing with them just because they are 3-4 months old (about how long it takes me to put on 100 hours) is stupid.
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Old 06-14-2019, 09:16 AM
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Originally Posted by homeby51 View Post
Why would I do a compression/leak test on a perfectly good running motor every 100 hrs? I could see if there were problems.....
So that you have a baseline and a trend and you can see issues before they become problems.
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