Iridium plug for stihl trimmer?
- Thread starter 97prizm
- Start date
I Googled stihl fs38 spark plug cross reference number. The autolite iridium came up as a match from napa. Maybe it was a mistake?
No - I've done more research and believe it to be correct. Autolite 2974 is the recommended plug for my BG86 blower and the XST2974 appears to be the Iridium version of it. I just ordered one to be delivered to my local NAPA.
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Bosch WSR6F for anything Stihl since the 70s I think.
You use a trimmer with the exhaust right next to your mouth and nose? I am fairly sure there is a warning pictogram stating something about that.
Next day delivery to my local NAPA store - such wonderful service!
![IMG_4704[1].JPG](https://bobistheoilguy.com/forums/attachments/img_4704-1-webp.221775/ "IMG_4704[1].JPG")
My chainsaw was refusing to start when hot so I decided to try the Autolite Iridium plug. It doesn't appear to have helped much but the saw is running well once it does start.
![IMG_4745[1].webp](https://bobistheoilguy.com/forums/attachments/img_4745-1-webp.223401/ "IMG_4745[1].webp")
I just got mine in a couple of days ago and am looking forward to how it'll run.
Supposedly 100LL is limited to 2 grams of lead per gallon.
I cut down a tree last night with the original Bosch plug then cut it up today with the new Autolite Iridium plug. The saw seems to be producing noticably more RPMs with the new plug. Now if I could just figure out why it doesn't like to start when hot... That's a relatively new development.
I plan to order another one of these for the Stihl leaf blower that was the original target for this plug. That machine typically takes three pulls to start when cold. We'll see if that changes.
You have a problem not plug related and you can’t rely on you ear to tell anything about the tune or rpm’s.
You will never get an impulse operated carb piece of equipment to start on the first pull. It needs the impulse from the engine turning to get the gas through the carb.
You will never get an impulse operated carb piece of equipment to start on the first pull. It needs the impulse from the engine turning to get the gas through the carb.
.45g/ Liter for the blue 100LL and 1.29g/ Liter for the "grape juice " ie purple fuel. Apparently the reno air races would bust out the purple stuff for the weekend.
What does pure Tetraethyl Lead look like? Is it a powder that dissolves in the gas, or a liquid? How much of it is pure Lead?
Since the atomic weight of lead is 207 I'm guessing most of the mass of tetraethyl Lead is Lead.
I like that cap. It must weigh 2 pounds on it's own. 
Based upon the experience an Autolite Iridium plug in my Stihl chainsaw I ordered two more. The first just went into a 5 HP Briggs flathead on my 1985 Troy-Bilt Pony rototiller. This machine had become difficult to start and often required starting fluid. With the new plug it fired on the first pull but didn't catch. It was off to the races on the second pull.
The Champion 5843 that came out had less than ten hours of use and as you can see is all carboned up. I am tempted to just clean it up and put it back in to see what happens.
![IMG_4826[1].webp](https://bobistheoilguy.com/forums/attachments/img_4826-1-webp.228680/ "IMG_4826[1].webp")
The Champion 5843 that came out had less than ten hours of use and as you can see is all carboned up. I am tempted to just clean it up and put it back in to see what happens.
93 E10 top tier with Amsoil Saber runs like a top in my Sthil Combi. It’s 10 years old now. Changed the plug once. Using factory type plug.
