Re: 4 cycle plug choices

I was working on my second plug after much flying, and blew it and the next one before I realized the output in my power panel had gone closed circuit and was vaporizing my plugs with 12VDC the instant I connected the clips. Grrr...

So when I saw two of these plugs (the ones recommended in the Saito instructions BTW) in a package for about three bucks more than a single OS, I thought that would be a plan. But indeed, I immediately suspected the tuning was fussier. I'll be interested to see if anyone else has similar observations too.

Thanks,

Mike D

I agree, the OS F although expensive gives the most consitent idle and performance. 150+ flights on a OS 26FS and was still going strong until I crashed the plane. About as many on various other OS FS engine sizes and a Saito 56. Seems to be one of those things that you install and walk away and forget about. It just keeps on working. I know Chris Chianelli who was the editor for Model Airplane News, used to say no matter what plug comes with your four stroke engine, if it is not an OS "F" replace it with one. My two bits. Cheers, Tom Thunder Bay ON Canada

Yeah, I thought I had read those sentiments somewhere, I'm sure it was something he wrote now that you mention it.

My experience with the Saito with OS "F" before was pretty much what you said - put it in, set it up, and forget about it. Never had to screw with it beyond initial tweaking at start of session. Tolerant of mixture variations, fuel changes etc. As it was my first four stroke I remember wondering what all the fuss about tuning four strokes was.

I'll run side by side comparison sometime when I have a new one of each at my disposal.

Thanks all,

Mike D

During the course of the last decade and a half racing four strokes, I have found that the OS F is the most durable and reliable (as far as getting ANY engine to run on it) of all that I tried. Each engine had its little quirks and one or another plug would work better under various circumstances. The plug I usually raced with in my OS .91 Surpass was the good old K&B 1L. Idling isn't real high on the racers list but high speed with a lot of nitro is. The Fox Miracle plug gave the best idle and transition of any I tested but was a bit too hot for good top end. The Thunderbolt four stroke plug worked well all around as did the newer Fox four stroke plug. My YS seems to prefer the OS F for most applications and an Enya 3 (or was it the 8?) ran a very close second.

My recommendation is to try a variety of plugs and see which works best for your engine/prop/fuel/environment.

Try a Fox with idle bar. You won't regret it.

-- Jim in NC

Done that. Almost a decade ago. I'll stick with the OS-F, thanks.

/daytripper

Paul have you tried the K&B 4C plug? I found it best if running high nitro. Gave an extra 300 RPM or so with a leaner mixture. Idled great if running high nitro. I like the Thunderbolt plug. Hotter than an OS-F and cheaper, don't know about durability yet. Enya 3 is also hotter than an OS-F though I have had a four stroke that wouldn't idle well with it.

Yes, if you are not willing to try a variety of plugs, the F is the one. Like I said, ANY four stroke that it fits will run on it.

And even if you are willing and have tried a variety of plugs, the F is still the one...

No, it's not. For racing, I have found that the K&B 1L works better for my OS .91 Surpass. I have also found that several others had some characteristics that I liked beter than the F. But, I was willing to try just about all of them.

Well, for starters --

Try what the manufacturer suggests. If that plug doesn't work for you, then try others. As a standard, the OS 'F" is a great all purpose plug. If you have problems, try a Fox Miracle Plug. If you have idle problems, try a K & B long idle bar plug. No such thing as "One size fits all".

Yes the OS-F is the one I allways start with and often end with. Well actually thats not right. Since it's rather easy to foul a plug when breaking in the engine I usually use a Fox Miricle plug for break in. Probably the best all round $4 plug and not as big of a loss if fouled.