4 cycle glow plug
 

I have an old sportster with a OS FS 40 in it. It gets around ok kinda scale flight you gotta think ahead for power.
Anyway my problem is when taxiing (we have a long taxiway) the plug gets cold and if I make it to the runway it
usually craps out trying to do a run up unless I have a ni-starter on it. I got 2 plugs to try and if I can pick the one that works first I can take the other back for the "good" one. The question is between a Mckoy 4C plug and a OS #6 (its the hotter plug) which one from experience is likely to work best ?? thanks bro's

I use an O.S. "F" plug in my four strokes, try one.

A four stroke glowplug typically has an extension at the tip to contain the heat in the glow element on the non-combustion cycle in a 4-stroke engine. A hot 2-stroke plug may not be enough for that situation. I have used the OS type F plug and the Fox Miracle plug on my 4-strokes with good results. There are other brands that I have used with success but I can't remember off-hand which they were.

Also, check your low speed needle setting to make sure that it is adjusted properly. If it is even slightly rich, it will cause the engine to quit after a long idle period.

I have found that the Fox Miracle plug works very well in all of my 4 strokes, 3 different brands.

Hmm sounds like the basin, are you really expected to taxi that huge distance? Any way you definitely need the OS type F.

John

Here's a picture, this 40 is not a surpass earlier ones had the head machined to create a pocket for the plug so standard plugs
would work better. I just found this out after looking at the motor again. bout 2 years ago when I bought it off ebay I found a manual and all it said was to use standard OS plugs....now I know why.
So now what do ya'll think ? hotter plug ?

http://i63.tinypic.com/25ja6bt.jpg

Are you sure about regular plugs? That inside lip looks like turbo plug configuration. Just wondering...

nothing longer than a standard plug will thread all the way.....yea I'm sure

Well then try the OS A6 which is one of the two you mentioned you were gonna try. The A6 is supposed to be the OS replacement for the former A3. The old A3 I believe was the hottest of the plugs intended for most of the smaller OS two strokes.

John

Thanks John...I was leaning there anyway didn't look like I was going to find someone with that experience.
Dang the Fox miracle plug seems to be the way of the dodo bird. Used it back in the 80's with all my saito's.
I use the OS "F type" in my Sportster bipe with a OS 70 surpass. I'll be back after some idle tests, couple days tops

P.S. John, yea it's the "basin"

Well I put off doing the lawn tonight and fired it up with the OS #6.. after a brief fight with the needles it runs awesome, crisp idle and throttle response....now to the field to get some flying. Oh gotta install a new battery the 1.5 years killed the one I had in it.

Man, I love happy endings.:cool:

Update:
Two flights today. we had cross winds and gusts, plus landing was from the unusual direction I'm still alittle
rusty. but two good takeoffs and two good landings with a few touchn'go's. was awesome to taxi all the way out
and I think I could have taken off without a runnup.

Congratulations Mike glad to see things worked out well for you:) Now I have a question you may be able to help me with I would like to make a return back there soon. And I wonder is the controlline circle (the one directly behind the parking lot and flight line) still avalible for controlline Use or has it been taken over entirely by cars? I would love to put in a few RC and Ukie flights while I am there.

It's still there and only designated for control line use, no R/C of any kind on the circles.

Thank you so much Mike that is the answer I was definitely hoping for. That will make my return visit so much more enjoyable being able to do some flights on the RC side then pop over to the other side of the parking lot and do some Controlline. :cool:

John

I know the OP got his engine running better, but I figured I'd offer my worthless two cents. Enya 3 plugs work fantastic in 4-stroke engines as well. I've used Fox idle bar hot plugs too with stellar results. Both the Fox idle bar and Enya 3 consistently ran better and gave better idle quality than an OS F plug though it seems the OP's engine won't accept the longer extended reach 4-stroke plugs anyway.