What a difference a spark plug makes!

JHZR2

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As some may recall, my old Robin Subaru inverter generator started on fire, so I got an HF Predator 3500 inverter. I was at about 20 hours, so I decided to do a break in oil change and spark plug exchange. The change from the HF “Torch” plug to an NGK iridium is a recommended upgrade.

The generator is quiet, but not low pollution. I can smell it much more than my 1700W robin or 1000W Honda, even when just idling. It also didnt idle perfect. Not bad, not troublesome, just not perfect.

All of that has changed with the NGK, idle sounds and smells much changed. The old plug didn’t look bad, the new one is just much better.
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From my activity on a GM truck forum, NGK and AC Delco plugs are the only plugs most use in their trucks. The ones that switch over to any other brand seem to have problems. As soon as they switch back all is well.

Especially for those that try the E3 plugs. Everyone on there say they run terrible and switch back. I have NGK in all my OPE.
 
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Surprised at the difference. Runs too cold? Edges wear off too fast and cause timing to retard? [Takes longer to build voltage so as to arc, thus I think it retards?]
 
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That plug reads too hot and the mixture reads rich. Is there a cap over the mixture screw or is it a fixed needle like later TECUMSEH S-K engines? Did you test in very warm weather. Also if there is a filter make sore the foam is not over oiled - and if its paper I would replace it with a foam block.
You may need rejetting if you cant adjust low speed jetting.

Also I would NOT use an extended nose firing tip plug in most ODPE engines.
 
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You guys are scaring me. I've never had such an easy starting engine as the Torch equipped Predators. As for fuel consumption, I notice that OHV engines are more efficient in general
 
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I bought a couple new Toro's that came with Torch plugs. First one I bought worked fine until about half way thru the summer when it started taking two or more pulls to start the mower. When I pulled the plug out it was covered in black fuzzy looking stuff. Freaked me out, new mower with a plug that looked like that so I took the plug down to the dealer and he said the heat range was to cool, gave me an NGK and problem fixed. Next new toro I didn't even start until I put a NGK in.
 
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I really like Bosch Platinum and have been using them for over 25 years. I've ran several sets to well over 100K miles and only changed them then because I felt guilty they'd been in so long. I used to run Bosch Platinum in my '88 Ford Escort sometimes running them 100-125K miles before changing them. When I did change them I couldn't tell any difference in the way the engine ran or fuel economy. I put a set of Bosch Platinum in a 20HP Kohler twin cylinder engine on my old riding mower years ago. When the mower wore out it still had the same set of plugs in it. Only Bosch Platinum that I've had that might have been product related is one I found once with a cracked insulator but I'd just had the plugs out for something, maybe a compression test so, I likely damaged it myself in the process. The car was running fine before I removed them and when I put them back in it was missing making me think it was user error. I guess my Versa has Iridium plugs in it so the verdict is still out as to how well I will like them since I've never used them before and this set only has about 25K miles on it. I just recently had to change the plug in my mom's riding mower but, no one had a listing for a Bosch Platinum for it so I ended using a Champion Platinum.
 

pbm

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I would consider NGK or Denso a jump up in quality from 'Torch'.
I generally stick to OE plugs...but having said that...I've had NO PROBLEMS running Autolite Iridiums in my Fords...
 
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When I did a plug change on my stationary Generac I put NGK Iridium's.
One of my old 2 stroke snowmobiles got a set of iridium plugs, ran it 8k miles on those plugs and sold it with them still in it, 2 shots on the primer and one pull starting no matter the temperature.
If I can get a iridium in the correct heat range it's the only plugs I use in my engines.
 

JHZR2

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That plug reads too hot and the mixture reads rich. Is there a cap over the mixture screw or is it a fixed needle like later TECUMSEH S-K engines? Did you test in very warm weather. Also if there is a filter make sore the foam is not over oiled - and if its paper I would replace it with a foam block.
You may need rejetting if you cant adjust low speed jetting.

Also I would NOT use an extended nose firing tip plug in most ODPE engines.

It’s a brand new generator. There’s no testing, it was routine service after 20ish hours.

The thing runs fine enough especially with the new plug. It mostly idles, sees a transient, supports 10-20A for maybe 20s, and then idles for a long while. So if anything, it’s from being too lightly loaded. But the whole thing runs better... it’s always been very quiet, but it is even smoother now then ever before, previously it had somewhat of a very slight misfire or miss or rumble when idling. No more of that.
 
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As some may recall, my old Robin Subaru inverter generator started on fire, so I got an HF Predator 3500 inverter. I was at about 20 hours, so I decided to do a break in oil change and spark plug exchange. The change from the HF “Torch” plug to an NGK iridium is a recommended upgrade.

The generator is quiet, but not low pollution. I can smell it much more than my 1700W robin or 1000W Honda, even when just idling. It also didnt idle perfect. Not bad, not troublesome, just not perfect.

All of that has changed with the NGK, idle sounds and smells much changed. The old plug didn’t look bad, the new one is just much better. View attachment 30610 View attachment 30611 View attachment 30612

Glad you like it, i have the iridium in my predator 4375 and it starts easy! Mainly i did not want the plug to fail during a power outage when i need it most, easier to change it to a known trusted brand ahead of time. The plug will also probably outlast my generator!
Astro_guy originally suggested to to me, as an upgrade.
 
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I would consider NGK or Denso a jump up in quality from 'Torch'.
I generally stick to OE plugs...but having said that...I've had NO PROBLEMS running Autolite Iridiums in my Fords...

Autolite is OEM for Ford so there shouldn't be problems. Ran a set of Autolites in a Toyota once and it started like crap and the idle was unstable. Switched to Denso, problem solved. Stick with OEM recommendation.
 
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Many plugs come with varnish on their terminal nuts (to prevent flashover and corrosion) , and if the wire boot or COP terminal spring doesnt wear thru the varnish - you will get misfire. Then you could have just be dirty or misgapped the plugs. nevr OPEN a gap so much that the GND electrode is heeled back - you'll get high misfire counts depending on how the plug is clocked in the cyl.

Autolite Ir plugs are being used by Subaru community as a MUCH lower cost and GREAT alternatve to the factory Ruthenium " "fingernail plugs" - a new design many may not be aware of; Likely to reduce cold start misfire or lean misfire
 
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