Hi. Im wondering what glow plug to use in my evolution 61nx. i know that evloution says to use their "super plug", but i heard that an os a3, or old #6 works. now, since my lhs didnt have the evo plug, (and they NEVER have what im looking for) i went with the a3. the a3 is a shorter plug, which means less compression, but its a hotter plug, and supposedly will ignite the fuel more completely. my question is, is there a plug out there that is as long as the evo plug, but hotter? in my mind, that would be the perfect plug. the engine runs well, but does let fuel slip by. im going to try the a3 as my evo plug took a crap on me yesterday. all you evo guys, let me know how my idea sounds and also if there is such a plug. thanks. everyone else, if you know of such a plug, chime in too!!! lol, thanks for any input you guys have.

I found that Fox Miracle plugs do very well in both my 2 stroke and 4 stroke engines. That is about all I use any more.

what temp range are they? evo plugs are hot, nothing less in temp works. i put an os 8 in, and it was missing and sputtering. so if thats a medium plug, it wont work.

In two strokes all I have ever used were the OS #8. These days I use four strokes for the most part and have started doing what Rod is and using the Miracle plug in everything, both two and four strokes. OS has priced themselves out of my flight box and the Fox plugs seem to work every bit as well for a lot less money.

that still doesnt answer my question. what heat range does the fox miracle plug operate at?

The Miracle plug was originally intended by fox to be used as a fourstroke plug and is of a medium hot range.

If you do not like your #6 A3 was a former designation and #6 is the current designation, The shorter reach is of no real concern and reduction of compression is negligible. Then consider trying the #7 This is a hotter plug than the medium #8.

John

FWIW, the heat of the plug isn't about igniting the fuel better. It's about changing the timing of the ignition. Your best power and reliability will come from getting the timing right, not by putting in the hottest plug.

I used fox pro eight for a long time, but the last card I bought had seven of the twelve plugs tips break loose. Kinda soured me on fox.

This is something no one mentions very much. I had a file on how to tune a two stroke at one point that I used to send to people asking about it. Sort of a lost art and one of the few things you can do to a glow engine. Most everyone now has a computer so they can do a search and look these things up. Maybe even do a search on RCU, it has been spoken of a number of times over the years.

I have at one time had at least a dozen different plugs in my tool box at the same time by trying to follow engine manufactures recommendations. I started a quest to find and limit myself to one two stroke and one four stroke plug that would work for all. Other than a few specialized engines I have found that the McCoy MC14 for two strokes and the YS plug for four strokes fit the bill. First I used the Fox Miracle Plug and the OS F but had a few duds with the Miracle plug so I tried others finally settling on the Hanger Nine HN3000 and HN 3002 performance plug. When they stopped supplying them I called and was told these were McCoy MC14's. I contacted McCoy and indeed that’s what they were. I have been running MC14's since and these plugs perform and last. Try one and see. For four strokes I use the YS plug over the OS it seems to last longer and run more consistently and is usually a little less in cost. I discovered the YS plugs when I bought my third YS motor and these were recommended to me. Be careful using the long reach plugs that they do not interfere with the piston. I find that the long reach plugs seem to perform better than the short ones. When you do a comparison compare two new plugs not one used and the other new. Use the old plug to tune the engine as best you can. Note idle, transition, midrange and top end. Now put the first new plug even if it’s the same as what is in the engine and re-tune for best performance. Swap it out with the second one and compare, re-tuning as necessary. You may be surprised that a simple plug change can turn an inconsistent engine into a rock solid performer with great idle, instant transition and as much as a 500 rpm increase at top end. There is a lot of talk about heat range but other than hot, medium and cold there is not much reference material as the plug manufactures have not standardized between brands.

If you have been monkeying with your carb you may have things out of whack so to get things roughly in the ball park set the carb up in this fashion to get you near factory defaults. You will need a small flat head screw driver, short length of fuel tubing and a 1/16 diameter wire or drill bit. Back the high speed needle out so it’s not going to be a factor. Place the fuel tubing on the fuel nipple with the other end in your mouth. Insert the 1/16 diameter in the carb throat and close the barrel until it just barely holds it. Blow through the tubing you should hear air escaping in the carb. Turn the low speed in until the air leak stops then back it out until you can just detect air passing into the carb. Open the carb and turn in the high speed until it just stops then open it the factory recommended turns. This will get you in the ball park to tune the engine.

Dennis

propworn, you interested in selling those two evo super plugs?? lol.

Not really I train students some which use these plugs its good practice to have one or two on hand for those days they burn one out. However you're in the US so my favaorite hobby shop Propshop Hobbies in Warren Michigan stocks all kinds of plugs and other goodies. http://www.propshophobbies.com/Searc...=evo+glo+plugs.

Propshop Hobbies will ship all over pretty reasonable from what I hear.

Dennis

ok, so i got an os a3 plug and put it in. my evo seems to like it. nice steady idle, and transitions nicely, and doesnt spit and sputter when i go w.o.t. thanks for all the advice guys. this is really a good substitution plug for this engine.