how would a 2-stroke engine run with a 4-stroke plug in it? i have lots of these "miracle" plugs that say 2 and 4 stroke but i think they are just 4 stroke plugs. i have an os .46 ax and i just put one of those plugs in it and it will run fine but won't idle... is the plug too cold?

Just use an OS #8. I have used the OS F 4 stroke plug is some 2 strokes, but they were bigger 1.40 pattern engines, they seemed to like them better for some reason.

4-stroke plugs tend to be hotter than most 2-stroke plugs. Some larger - more than 20cc - engines often run better with 4-stroke plugs. When used in smaller - ie .40 size engines - with 10-15% nitro content fuels, the plug might not last long.

Safe Flying!

i will change the plug as soon as i get the new ones in the mail from tower. could this plug be the cause of my idle troubles? because the engine ran perfectly before the last plug burned out

That plug is fine in a .46 engine, the first engine I ever used one in was an OS
.46....it made a crappy engine run real nice. They really work well in inverted
applications too, because it has an extended tip, and does not drown out easily.

FBD.

that is wonderful news! as soon as i finish building my ultra sport i'm taking the o.s. out of my girlfriend's trainer and putting it in the ultra sport inverted. guess i will stick with these longer plugs for that reason. she's getting the crappy tower hobbies .46 [sm=tongue.gif] now i'm trying to figure out my idle problem... i wish i was better with engines and knew how to fix these things myself! anyway, maybe y'all can help me on this one. i took out her trainer 2 days ago to fool around with and it wouldn't start, then realized the plug had burned out so i replaced it with the miracle plug... still wouldn't start. then i realized the bigger needle valve (don't know if it's low- or high-speed) was turned in all the way closed, so i turned it out to what i thought would be an acceptable setting.

still won't start.

primed the engine with my finger over the muffler and flipped the prop a few times.

it started! after it got running i leaned out the big needle valve to max rpms and then richened it a few clicks like i always do. it transitioned perfectly, revved up to normal rpm then when i brought the throttle back to idle, the engine ran at a higher-than-normal idle rpm and slowly lowered until it finally died, which occurred about 10 or 15 seconds after i brought it back to idle. i started it again and had the same problem over and over again, so i just came home

if it isn't the glow plug, i can't figure it out. my best friend who i always go flying with is an engine master and would be able to just say ohhhhhhhh your flux capacitor whatchamacallit isn't tuned right and would fiddle around for a few seconds and it would run fine, but he has got a second job and i can't get together with him to help me. maybe you guys can

thanks a whooole lot
bill

It sounds like your low speed needle is set too rich. Turn it in 1/8 turn at a time
till the idle improves. Once you find the sweet spot, the engine will run like a top.

Be sure to reset the high speed. Peak the engine all the way to highest revs,
then open the main needle until you hear the rpms drop a little.

FBD.

HI! Flyboy Dave...
I see a lot of your post and I agree all of them
my question is about 2 cycle engine setting

if is possible to have a post in the first page of this forum about how to set a 2 strokes engine: this IMO can help the new member how run correcly the 2 strokes before puting a lot of post about funny runing

i think the new member start with a trainer w 2 strokes engine

tigil....thank you for the kind words. [sm=thumbup.gif]

I have been planning a "how to" on setting-up and running a new engine for
the guys that are starting out....I think it is a good idea also.

FBD.