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Discussion Starter · #1 ·
A friend of mine needs an iridium plug for a Firman PO7571. It's the same generator I pulled the scope waveforms from. I checked the manual and the plug reference is a Champion N9YC. The cross reference website pulls up 216 possible plugs that would work. In that list, 26 of them are NGK plugs. I don't know which ones are iridium plugs, if any of them are. I could use some help narrowing down the choices. The plugs appear to be different heat levels as well.

It doesn't appear to use the same plug as the GN400i or my Firman.
 

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I think all the iridium NGKs end in IX, do they not? That BPR6EIX is the same plug my dual fuel Champion uses. I was able to walk into the local Autozone and pick one up. But make sure you have that other number, 6637. When I asked for the plug by the BPR number they couldn't find it. But when I said 6637, no problem. When they brought it to the counter it said BPR6EIX on it. Go figure...
 

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Discussion Starter · #5 ·
Thanks for the info! I will pass that along to my friend. He finally got the replacement parts from Firman for the electric start. He replaced the switch but that did not fix the problem. He has not yet replaced the solenoid. He said he gave it a whack with a screwdriver and it worked. So it's definitely a flaky solenoid.
 

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I think all the iridium NGKs end in IX, do they not? That BPR6EIX is the same plug my dual fuel Champion uses. I was able to walk into the local Autozone and pick one up. But make sure you have that other number, 6637. When I asked for the plug by the BPR number they couldn't find it. But when I said 6637, no problem. When they brought it to the counter it said BPR6EIX on it. Go figure...
So I am also trying to get a replacement plug and if I could confirm a compatible iridium plug i would go that route. But I can't even find a non-iridium plug that does not have a resistor. I checked with Firman support and they only recommend the following plugs LG F7TC, Champion N9YC, NGK BP6ES or BP7ES. I can't find any store that has the Champion or the NGK. They have the resistor version RN9YC or BPR7ES, BPR6ES but Firman is saying those are not compatible with the gen. They are sending me one LG F7TC for free. What are your thoughts on whether a resistor plug can be used in place of a non-resistor plug?
 

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So I am also trying to get a replacement plug and if I could confirm a compatible iridium plug i would go that route. But I can't even find a non-iridium plug that does not have a resistor. I checked with Firman support and they only recommend the following plugs LG F7TC, Champion N9YC, NGK BP6ES or BP7ES. I can't find any store that has the Champion or the NGK. They have the resistor version RN9YC or BPR7ES, BPR6ES but Firman is saying those are not compatible with the gen. They are sending me one LG F7TC for free. What are your thoughts on whether a resistor plug can be used in place of a non-resistor plug?
less noise with the resistor plug.
 

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I assume you mean less noise in electronics like radios. I found the following which discusses using non-resistor plugs in engines designed for resistor plugs but not the other way around. The part about resisting some of the spark energy is what causes me pause on using a resistor plug.

What is a Resistor Spark Plug?



Spark Plug Resistor Location



At the moment the spark jumps the gap it causes a high frequency burst of energy, known as RFI (radio frequency interference). RFI, as its name suggests, creates static on your radio and interference with other electronic equipment, including the vehicle’s on-board electronic control units (ECUs).


Resistor plugs were developed in the 1960s to suppress some of the spark energy, thus lowering RFI to an acceptable level. Most resistor spark plugs use a monolithic resistor, generally made of graphite and glass materials, to filter the electrical voltage as it passes through the center electrode.


Since resistor type plugs actually “resist” some of the spark energy, non-resistor type plugs actually deliver a more powerful spark. It is for this reason that most racing plugs are non-resistor types. However, in most automotive applications, a resistor plug is required for proper vehicle operation. Use of non-resistor plugs in vehicles that call for a resistor type can result in rough idling, high-rpm misfire, and abnormal combustion.
 

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I guess I'm a majority of one, but don't see the need for precious metal iridium/NGK plugs? Granted the more expensive plugs do last longer and provide a hotter or more intense spark in a vehicle, but in an occasional use generator? OK, if you're in hurricane country or out west with whatever disaster they're currently dealing with requiring run times of days not hours it might make sense.

Anyway, have always used the garden variety plugs the OEM recommends with no issues. Also have spare plugs JIC. , I've seen bad plugs out of the box, and having a few new $2 plugs on hand is cheap insurance. I gave away a 20 year old Generac 3250 which still had the original plug. I'd cleaned and checked the gap a few times but always started and ran well. Gave it away as it probably had 250 hours and I don't trust the lower cost units when they approach 300 hours.
 

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Yeah, Ida definitely changed my perspective on how to prepare for post hurricane survival. I am thinking of getting a backup gen in case my main one fails. I sold my old 5k gen and now wish I had kept it. Extra parts is easy so taking care of that.

On spark plugs, I was able to find a champion N9YC (recommended by manufacture) so pickup one of those. Now I'll have two spare plugs.
 

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Yeah, Ida definitely changed my perspective on how to prepare for post hurricane survival. I am thinking of getting a backup gen in case my main one fails. I sold my old 5k gen and now wish I had kept it. Extra parts is easy so taking care of that.

On spark plugs, I was able to find a champion N9YC (recommended by manufacture) so pickup one of those. Now I'll have two spare plugs.
Yep. I bought a little $400 FIrman as a backup to my larger unit. No issues with larger one, just the weather this year has been strange and am kind of dreading this winter.
 

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I guess I'm a majority of one, but don't see the need for precious metal iridium/NGK plugs? Granted the more expensive plugs do last longer and provide a hotter or more intense spark in a vehicle, but in an occasional use generator? OK, if you're in hurricane country or out west with whatever disaster they're currently dealing with requiring run times of days not hours it might make sense.

Anyway, have always used the garden variety plugs the OEM recommends with no issues. Also have spare plugs JIC. , I've seen bad plugs out of the box, and having a few new $2 plugs on hand is cheap insurance. I gave away a 20 year old Generac 3250 which still had the original plug. I'd cleaned and checked the gap a few times but always started and ran well. Gave it away as it probably had 250 hours and I don't trust the lower cost units when they approach 300 hours.
the only time we use the iridium is on the NG and LP gens or gen conversions when only on the LP or NG as the primary fuel..
they take the clean burn better and have a fine point for the spark.
and .022-.025 inches for the gap.

if you are on gasoline i switch back to the copper ngk plug with a standard oem gap.

yea the resistor plug drops the current down for better am radio reception.
and has to do with computer noise as well or interference.
think wifi and blue tooth...
if it is hot enough of a noise it can blank or swamp out a computer.

some spark systems are designed for solid spark plugs...
most are resistor plugs.
 

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Yep. I bought a little $400 FIrman as a backup to my larger unit. No issues with larger one, just the weather this year has been strange and am kind of dreading this winter.
i saw an all black caterpillar today...
they say it is a sign of a bad cold winter.
yup a spare gen in these times is part of a great plan!
 

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i saw an all black caterpillar today...
they say it is a sign of a bad cold winter.
yup a spare gen in these times is part of a great plan!
I've seen a couple of those, yellow jackets disappeared early which was good for mowing, neighbor said his cattle are getting wooly early this year. "The times they are achanging" for sure. Plan for the worst, hope for the best I guess.
 
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