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Standard spark plugs vs. iridium.........

#1

B

BTBO

I have a Scag Liberty 48" with the Kawasaki FR651V. All is well in terms how it runs, but at some point will change the spark plugs. Do the iridium plugs have enough benefits to justify the higher cost?


#2

B

bertsmobile1

No
But I fear we will end up with another synthetic vs plain oil or detergent vs non detergent oil type debate .
Every one who does not have the background knowledge to understand the what & whys will come in ardently throwing hundreds of you tube videos from equally ignorant ego maniacs as if that is somehow proof of some sort , along the lines of east poo cause 5,000,000,000 can not all be wrong.
On some CAR engines the computer controllers need to get clean reliable signals and in that case the exotic metal plugs might be needed.
Mower engines are the cheapest engines that it is possible to make
They run relatively low compression,
They run fixed timing now everyone has given up on electronic variable timing
They run at a fixed speed
And the speed is very low.

Having said all of that, if your mower engine is worn out to the point it gobbles up a pint of oil every time you mow then the exotic plugs will still work long after standard plugs have given up the ghost .

Think about it.
A modern 500cc motorcycle engine is pumping out anything from 50 to 100 Hp with red lines around the 10,000 rpm mark and most of them a fine with standard plugs
A modern 500 Cc mower engine is hard put to pump out 20Hp.

But if it makes you feel better than the man next door then go ahead, the parts retailers need your money .


#3

Hammermechanicman

Hammermechanicman

My spark plug is better than your spark plug because the internet says so.


#4

M

MParr

No


#5

bkeller500

bkeller500

If you talking (2) spark plugs.......why not? Why not try them out and see if you notice any benefit?


#6

Scrubcadet10

Scrubcadet10

People have reported better throttle response with NGK iridium plugs.... however that may be the placebo effect.


#7

Scrubcadet10

Scrubcadet10

Hammermechanicman said:
My spark plug is better than your spark plug because the internet says so.
Click to expand...
Your spark plug isn't better than my spark plug because the T.V. says so...


#8

Hammermechanicman

Hammermechanicman

My spark plug gets 200,000 miles in my string trimmer before I have to replace it.


#9

Scrubcadet10

Scrubcadet10

Hammermechanicman said:
My spark plug gets 200,000 miles in my string trimmer before I have to replace it.
Click to expand...
My Cummins gets 250,000 before i change the plugs in it.......


#10

7394

7394

Scrubcadet10 said:
My Cummins gets 250,000 before i change the plugs in it.......
Click to expand...
:ROFLMAO:


#11

7394

7394

I have the same model Liberty, & since my former Toro had the same Kawasaki engine & I was stocked up. I will be using the OE NGK plugs, till my supply runs out.


#12

Scrubcadet10

Scrubcadet10

I believe there was an old ford that would spit the plugs out when it was time to change them.


#13

Newokie1959

Newokie1959

BTBO said:
I have a Scag Liberty 48" with the Kawasaki FR651V. All is well in terms how it runs, but at some point will change the spark plugs. Do the iridium plugs have enough benefits to justify the higher cost?
Click to expand...
Here's how I see this. The OEM (Kawasaki) designed, built, tested and THEN produced and sold that engine. They know what works best. Go with that.


#14

S

SamB

bertsmobile1 said:
No
But I fear we will end up with another synthetic vs plain oil or detergent vs non detergent oil type debate .
Every one who does not have the background knowledge to understand the what & whys will come in ardently throwing hundreds of you tube videos from equally ignorant ego maniacs as if that is somehow proof of some sort , along the lines of east poo cause 5,000,000,000 can not all be wrong.
On some CAR engines the computer controllers need to get clean reliable signals and in that case the exotic metal plugs might be needed.
Mower engines are the cheapest engines that it is possible to make
They run relatively low compression,
They run fixed timing now everyone has given up on electronic variable timing
They run at a fixed speed
And the speed is very low.

Having said all of that, if your mower engine is worn out to the point it gobbles up a pint of oil every time you mow then the exotic plugs will still work long after standard plugs have given up the ghost .

Think about it.
A modern 500cc motorcycle engine is pumping out anything from 50 to 100 Hp with red lines around the 10,000 rpm mark and most of them a fine with standard plugs
A modern 500 Cc mower engine is hard put to pump out 20Hp.

But if it makes you feel better than the man next door then go ahead, the parts retailers need your money .
Click to expand...
I put Motorcraft iridium plugs in my Ford Ranger 4.0 because they are so difficult to get to change. I don't want to do it any more often than I need to.
My mowers are super easy to get to the plugs. A buck and a half OEM replacement plug works just as well as a $6.00 plug.


#15

B

Briantii

I'd say iridium are for sure "better" technically and they will last longer assuming you have no negative factors affecting the plugs like overheating or fouling. With that said - will you EVER realize any real benefits to justify the costs? Probably not.

Our airplane has a 5.9 liter 6 cylinder air cooled engine making 200hp turning 2700 rpm with dual spark plugs and dual independent magneto fixed timing ignition. Fairly similar to a mower engine in hp per liter and RPM. We run iridium plugs in it because of significantly longer plug life, slightly better low idle smoothness (maybe), easier starting (maybe), and reduced maintenance because the electrodes for them are smaller and re-gapping isn't required. Regular copper plugs last ~400 hours in an aircraft engine, and iridium plugs (also known as "fine wires") can last up to 2000 hours. It's worth it on the aircraft despite some absolutely eye watering prices.

I wouldn't bother on a lawn mower engine though despite the technology being superior. It just doesn't practically make a big enough difference and swapping a plug on a mower every 250 - 500 hours and takes all of 2 minutes and will probably never save you money or hassle.

Yes it's better, no you probably don't need or want it.


#16

upupandaway

upupandaway

Electricity arcs easier from sharp edges. They say Iridium tip plug is harder than copper plug so it hold the sharp edge longer.
I think plugs are like oil. My car had 150K when i looked inside the cylinder. The hatch marks are still there. I use dino oil. Maybe synthetic is better for extremes that my car never reaches so it lubes the same. I'm sure my replacing my plugs is the same as my oil experience.

1634748077055.png1634748078905.png


#17

matt man

matt man

My spark plugs suck, Why do they put resistor plugs on mowers? I'v had 6 mowers with bad plugs this month. Mostly NGK r


#18

H

Hal12

Bought the snapper in 91 I think. Still runs great...never changed the plugs. Maybe I should..


#19

matt man

matt man

Hal12 said:
Bought the snapper in 91 I think. Still runs great...never changed the plugs. Maybe I should..
Click to expand...
Don't do It, Bad omen


#20

B

Briantii

matt man said:
My spark plugs suck, Why do they put resistor plugs on mowers? I'v had 6 mowers with bad plugs this month. Mostly NGK r
Click to expand...

Wow that's surprising. I wonder if someone got a batch of the fake NGK's from Amazon / eBay.


#21

Scrubcadet10

Scrubcadet10

a lot of NGK fakers out there. go to a local auto part store that carries NGK etc


#22

gamma_ray

gamma_ray

BTBO said:
I have a Scag Liberty 48" with the Kawasaki FR651V. All is well in terms how it runs, but at some point will change the spark plugs. Do the iridium plugs have enough benefits to justify the higher cost?
Click to expand...
I don't think so. As easy as mower plugs are to change, go with standard ones.


#23

S

SamB

Scrubcadet10 said:
Your spark plug isn't better than my spark plug because the T.V. says so...
Click to expand...
My spark plug(s) are better than your's because I draw little smiley faces in the insulators! So there! :-D


#24

B

bertsmobile1

Briantii said:
I'd say iridium are for sure "better" technically and they will last longer assuming you have no negative factors affecting the plugs like overheating or fouling. With that said - will you EVER realize any real benefits to justify the costs? Probably not.

Our airplane has a 5.9 liter 6 cylinder air cooled engine making 200hp turning 2700 rpm with dual spark plugs and dual independent magneto fixed timing ignition. Fairly similar to a mower engine in hp per liter and RPM. We run iridium plugs in it because of significantly longer plug life, slightly better low idle smoothness (maybe), easier starting (maybe), and reduced maintenance because the electrodes for them are smaller and re-gapping isn't required. Regular copper plugs last ~400 hours in an aircraft engine, and iridium plugs (also known as "fine wires") can last up to 2000 hours. It's worth it on the aircraft despite some absolutely eye watering prices.

I wouldn't bother on a lawn mower engine though despite the technology being superior. It just doesn't practically make a big enough difference and swapping a plug on a mower every 250 - 500 hours and takes all of 2 minutes and will probably never save you money or hassle.

Yes it's better, no you probably don't need or want it.
Click to expand...
but does you lawnmower run under lean burn conditions at 30,000 feet ?
Is your mower running on 100 octane avgas ?
FWIW I probably pull around 200 plugs a year out of engines and of these 200 plugs 190 would get the plug gap adjusted & replaced
The only time a plug actually needs to be replaced is if it is damaged or worn out
Worn out is when the center electrode is level with the insulator nose or the insulator has started to crack & break up from the effect of thermal cycling
Got dozens of customers with engines still running the same plugs as they were when I first saw them 9 years ago and for may of them that is better than 1000 hours ago.
Then again my aim in business is to have happy customers not to fleece them for every last cent that can be justified .


#25

B

bertsmobile1

matt man said:
My spark plugs suck, Why do they put resistor plugs on mowers? I'v had 6 mowers with bad plugs this month. Mostly NGK r
Click to expand...
You have problems with either your fuel quality or with your ignition.
No plug brand is significantly better than any other in the same price grouping.
Every plug that comes off the machine is subjected to a variety of tests and sorted out according to the results
Top quality goes into individual boxes
Lowest quality goes into supermarket blister packs with a house name printed on the side .
Because of our friends in California, the maximum lever of lead acceptable in exhaust is < 0.00001 %
At that level the 1 molecule of lead that is liberated from the glaze on the insulator nose per hour will push the emissions over the limit, despite the fact that it is part of the glaze and so strongly attached to it that you would need a volcano to seperate the lead from the porclean.
So the noses are not glazed
In order to make higher profits the oil companies blend "fuel" which is NOT PETROL out of all sorts of otherwise unuseable volatile liquids .
Now old real petrol did not conduct electricity untill it made a thick continious film on the plug combine with free carbon.
Modern fuel vapour is highly conductive at cylinder compression
So if the engine does not fire right up then the "fuel" deposits a fine film of conductive material all over the plug and because the nose is not glazed it stays there so you end up with a leakage palth down the insulator of lower resistance than the gap so that is where the electricity goes.

HAving said that any one who buys anything from Ebay or Amazon where you never actually know who the actual vendor is are begging to be ripped off by criminals selling counterfeit goods or genuine parts that were supposed to be sent for scrap recovery but got diverted by a middle man to be sold to cheapskates.
Hundreds of real stores you can walk into & buy genuine spark plugs from a real person


#26

upupandaway

upupandaway

SamB said:
My spark plug(s) are better than your's because I draw little smiley faces in the insulators! So there!
Click to expand...
I draw lightning on mine. I swear my riding mower cut quicker when i painted flames on the sides.../s


#27

T

txmowman

It's a lawn mower engine. Iridium plugs will make no difference, same as using premium fuel will make no difference. But, it's your $$


#28

S

SamB

upupandaway said:
I draw lightning on mine. I swear my riding mower cut quicker when i painted flames on the sides.../s
Click to expand...
Dang! Bested again! Lightning AND flames!?
(I don't suppose flame DECALS would be better than PAINTED ones, would they?)


#29

S

slomo

Standard copper plugs with no resistor if you can snag them. No need to reinvent the wheel.


#30

A

aussielawny

txmowman said:
It's a lawn mower engine. Iridium plugs will make no difference, same as using premium fuel will make no difference. But, it's your $$
Click to expand...
This ^^


#31

Hammermechanicman

Hammermechanicman

"It's a lawn mower, not the space shuttle" to quote a utuber. And i agree.


#32

7394

7394

Yup..


#33

B

bertsmobile1

slomo said:
Standard copper plugs with no resistor if you can snag them. No need to reinvent the wheel.
Click to expand...
This will change the timing of the spark or top be more precise allow the spark to jump at a lower voltage .
This can lead to the spark tacking down the sides .
Electricity can not be made to move faster other than by super cooling the conductors
So all circuitry slows the electricity down
The circuitry in the magneto is designed to slow the spark down just the right amount of time .
Lowering the resistance will allow it to happen earlier than planned
Weather this is significant or not in a mower engine is a matter of opinion


#34

Hammermechanicman

Hammermechanicman

Back in the 90s the 5hp briggs go cart racers had the resistor vs nonresistor debate. The most difference i ever saw was about 1 degree of difference which is insignificant in any stock enhine. On some small 2 strokes with low energy magnetos using a resistor plug OR too wide of a gap can cause poor running due to misfires.


#35

S

slomo

Hammermechanicman said:
Back in the 90s the 5hp briggs go cart racers had the resistor vs nonresistor debate. The most difference i ever saw was about 1 degree of difference which is insignificant in any stock enhine. On some small 2 strokes with low energy magnetos using a resistor plug OR too wide of a gap can cause poor running due to misfires.
Click to expand...
And many a tug to fire off the ol' girl.


#36

T

Tucson47

No, I would not spend the money on Iridium.
I switched to Champion's "EcoClean" plugs on my AC130 for quicker cold starts. They function with the same performance benefits as an Iridium plug, in that they both have the very fine wire electrode......just not the precious metal, nor the $$$ price tag. They do however last WAY longer than a standard wide tipped spark plug.


#37

Hammermechanicman

Hammermechanicman

Does anyone have in specific info on the difference between champion regular, long life and eco clean plugs?


#38

J

Joed756

I've spent over 5o years now mowing lawns and most of that time I'm letting my mind wander just imagining how much better my life would be with exotic metal spark plugs in my mower.


#39

J

Joed756

Briantii said:
I'd say iridium are for sure "better" technically and they will last longer assuming you have no negative factors affecting the plugs like overheating or fouling. With that said - will you EVER realize any real benefits to justify the costs? Probably not.

Our airplane has a 5.9 liter 6 cylinder air cooled engine making 200hp turning 2700 rpm with dual spark plugs and dual independent magneto fixed timing ignition. Fairly similar to a mower engine in hp per liter and RPM. We run iridium plugs in it because of significantly longer plug life, slightly better low idle smoothness (maybe), easier starting (maybe), and reduced maintenance because the electrodes for them are smaller and re-gapping isn't required. Regular copper plugs last ~400 hours in an aircraft engine, and iridium plugs (also known as "fine wires") can last up to 2000 hours. It's worth it on the aircraft despite some absolutely eye watering prices.

I wouldn't bother on a lawn mower engine though despite the technology being superior. It just doesn't practically make a big enough difference and swapping a plug on a mower every 250 - 500 hours and takes all of 2 minutes and will probably never save you money or hassle.

Yes it's better, no you probably don't need or want it.
Click to expand...
Why dual spark plugs? Is it for redundancy sake or a more thorough burn?


#40

J

Joed756

"genuine parts that were supposed to be sent for scrap recovery but got diverted by a middle man to be sold to cheapskates."

I had a friend who's job it was to take the dented, damaged Bud cans from the brewery to be destroyed. A lot of them seemed to fall from the truck. I am a cheapskate, but couldn't see a downside there.


#41

Hammermechanicman

Hammermechanicman

Joed756 said:
I've spent over 5o years now mowing lawns and most of that time I'm letting my mind wander just imagining how much better my life would be with exotic metal spark plugs in my mower.
Click to expand...
When mowing i wonder about reverse electron charged passivated mower blades. I hear they are the best.


#42

B

Briantii

Joed756 said:
Why dual spark plugs? Is it for redundancy sake or a more thorough burn?
Click to expand...

Redundancy - mag failures (points wear, etc) and lead fouled spark plugs are fairly common. Both sets are fully tested and functional before flight.


#43

B

Briantii

bertsmobile1 said:
but does you lawnmower run under lean burn conditions at 30,000 feet ?
Is your mower running on 100 octane avgas ?
FWIW I probably pull around 200 plugs a year out of engines and of these 200 plugs 190 would get the plug gap adjusted & replaced
The only time a plug actually needs to be replaced is if it is damaged or worn out
Worn out is when the center electrode is level with the insulator nose or the insulator has started to crack & break up from the effect of thermal cycling
Got dozens of customers with engines still running the same plugs as they were when I first saw them 9 years ago and for may of them that is better than 1000 hours ago.
Then again my aim in business is to have happy customers not to fleece them for every last cent that can be justified .
Click to expand...

No, but you clearly missed the point. I was simply pointing out there can be advantages but my conclusion was essentially the same as yours - A WASTE OF MONEY AND NOT WORTH IT IN A MOWER. Hopefully that's clear enough.


#44

B

bertsmobile1

Joed756 said:
Why dual spark plugs? Is it for redundancy sake or a more thorough burn?
Click to expand...
Because some times there are no clouds handy to pull up onto so you can change a fouled plug.
So yes failsafe redundency


#45

H

hlw49

I have a Tanaka TCB 340 32 cc 1.8 hp String Trimmer I bought in 2004 and still has the original plug and have never had to do a carb. job on it. Run 100% pure gas and Stihl synthetic oil in it. She is a beast of a trimmer. Just trimmed the place with her today.


#46

S

SamB

hlw49 said:
I have a Tanaka TCB 340 32 cc 1.8 hp String Trimmer I bought in 2004 and still has the original plug and have never had to do a carb. job on it. Run 100% pure gas and Stihl synthetic oil in it. She is a beast of a trimmer. Just trimmed the place with her today.
Click to expand...
Yes,stay away from pump gas!


#47

E

enigma-2

Scrubcadet10 said:
a lot of NGK fakers out there. go to a local auto part store that carries NGK etc
Click to expand...
FYI, how to tell a fake NGK plug:

www.diycarserviceparts.co.uk

Counterfeit NGK Spark Plugs | How to Avoid Fake Spark Plugs

With stories of buyers being caught out by counterfeit NGK spark plugs, here's how you can spot fake spark plugs and ensure you only buy genuine plugs.
www.diycarserviceparts.co.uk www.diycarserviceparts.co.uk


#48

H

hlw49

SamB said:
Yes,stay away from pump gas!
Click to expand...
So what do you suggest people us VP fuel or something similar.


#49

S

SamB

hlw49 said:
So what do you suggest people us VP fuel or something similar.
Click to expand...
Several places around here sell "Ethanol-free" gasoline. One CAN use regular "pump" gas, but it's risky and usually ends up badly. Evan an ultrasonic parts cleaner won't get all the disintegrated fuel lines out of those itty-bitty passages when the ethanol dissolves the fuel lines. Ethanol cannot be effectively removed from blended gasoline. It CAN be romoved, but what you end up with is about 80 octane. I may have an advantage because I live close to a refinery that distributes ethanol-free gasoline to any station that wants it for OPE users.


#50

H

hlw49

SamB said:
Several places around here sell "Ethanol-free" gasoline. One CAN use regular "pump" gas, but it's risky and usually ends up badly. Evan an ultrasonic parts cleaner won't get all the disintegrated fuel lines out of those itty-bitty passages when the ethanol dissolves the fuel lines. Ethanol cannot be effectively removed from blended gasoline. It CAN be romoved, but what you end up with is about 80 octane. I may have an advantage because I live close to a refinery that distributes ethanol-free gasoline to any station that wants it for OPE users.
Click to expand...
I have a Tanaka TCB 340 32 cc 1.8 hp String Trimmer I bought in 2004 and still has the original plug and have never had to do a carb. job on it. Run 100% pure gas and Stihl synthetic oil in it. I rest my case.


#51

E

enigma-2

hlw49 said:
I have a Tanaka TCB 340 32 cc 1.8 hp String Trimmer I bought in 2004 and still has the original plug and have never had to do a carb. job on it. Run 100% pure gas and Stihl synthetic oil in it. I rest my case.
Click to expand...
If it were me, I'd drop a new plug in it, plus new air and fuel filter. Even if it still runs, these parts do wear out and one every 17 years is cheap enough ....


#52

3

350Rocket

Personally I have not noticed a difference in performance between spark plugs on any of the engines I've owned. I replace them as preventative maintenance, but usually when they get replaced they could have gone much longer before causing any issues.


#53

bkeller500

bkeller500

I don't think I have ever had a bad spark plug or noticed a better running motor when I changed them. From tractors, cars, trucks, boats, chainsaws......you name it. But I did change them anyway as part of a maintenance. But then again I never had motor troubles and that may be why.


#54

H

hlw49

enigma-2 said:
If it were me, I'd drop a new plug in it, plus new air and fuel filter. Even if it still runs, these parts do wear out and one every 17 years is cheap enough ....
Click to expand...
I think I'll wait until next year now LOL mowing season is about over now.


#55

3

350Rocket

bkeller500 said:
I don't think I have ever had a bad spark plug or noticed a better running motor when I changed them. From tractors, cars, trucks, boats, chainsaws......you name it. But I did change them anyway as part of a maintenance. But then again I never had motor troubles and that may be why.
Click to expand...
At least on automotive applications ignition coils seemed to fail more frequently when people didn't change their plugs on time. It might not be a big issue on older mower engines but the later ones that seem to he prone to coil failure could very well be susceptible to this problem also.
So even though everything is running fine before and after its still worth changing at a reasonable interval.


#56

C

clubairth

The reason for Platinum and Iridium plugs is for longevity. That's how the car companies get the 100K mile rating for changing plugs. Now if you race or are into hi performance you will soon find out Copper is usually the plug of choice. BUT that also means much shorter service intervals like 30K or so.

I have a super charged car and have added a larger lower pulley a tune and a larger IC. My tuner says if I add a smaller upper pulley I will need to go to Copper plugs. The car is hard to change plugs so for now I am sticking with the factory called for Iridium plugs.
.
.
.


#57

S

SamB

clubairth said:
The reason for Platinum and Iridium plugs is for longevity. That's how the car companies get the 100K mile rating for changing plugs. Now if you race or are into hi performance you will soon find out Copper is usually the plug of choice. BUT that also means much shorter service intervals like 30K or so.

I have a super charged car and have added a larger lower pulley a tune and a larger IC. My tuner says if I add a smaller upper pulley I will need to go to Copper plugs. The car is hard to change plugs so for now I am sticking with the factory called for Iridium plugs.
.
.
.
Click to expand...
I use OEM Iridium plugs almost solely because of the 'hard to change' factor on my 4.0 OHV Ranger. Oil change is a lark compared to lug changes!


#58

E

enigma-2

SamB said:
Oil change is a lark compared to lug changes!
Click to expand...
Why are you dragging Studebaker in on this?

Lark was a Studebaker model ....
(groan)


#59

Hammermechanicman

Hammermechanicman

enigma-2 said:
Why are you dragging Studebaker in on this?

Lark was a Studebaker model ....
(groan)
Click to expand...
Somebody showing their age.


#60

E

enigma-2

Sorry. Us old farts have a tendency to talk about back in the day, a bit.


#61

matt man

matt man

Briantii said:
Wow that's surprising. I wonder if someone got a batch of the fake NGK's from Amazon / eBay.
Click to expand...
No these are repair jobs on push mowers. I misdiagnosed a friends pressure washer (brand new, tractor supply, marked way down) , Thought it was the coil, Found out was the plug. after buying a coil for it. Ended up using coil on another honda engine. because kill wire was not working.


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