os f plug
05-31-2010, 05:35 PM
#2
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RE: os f plug
The "F" plug is for 4-stroke engines. It is longer than the 2-stroke plugs and is a hotter plug. Some people will use the longer plug in a 2-stroke engine for better performance with low nitro fuel, but I can't see the advantage. Just use a hotter 2-stroke plug. And yes, it may hit the piston.
05-31-2010, 06:53 PM
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RE: os f plug
You can check by pulling the head off and installing the plug. You will see if it protrudes beyond the head. I have one in an OS 55ax and clears fine.
05-31-2010, 07:21 PM
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RE: os f plug
Hi,
The main advantage with a four stroke plug is it provides a more reliable idle, (like when you are landing) in inverted two stroke motors. With motors mounted vertically or on their side there isn't any real advantage. A four stroke plug is designed and manufactured to keep glowing between ignition strokes which in a four stroke, (if my maths is correct) are exactly half those of a two stroke
.
Cheers,
Colin
The main advantage with a four stroke plug is it provides a more reliable idle, (like when you are landing) in inverted two stroke motors. With motors mounted vertically or on their side there isn't any real advantage. A four stroke plug is designed and manufactured to keep glowing between ignition strokes which in a four stroke, (if my maths is correct) are exactly half those of a two stroke
.Cheers,
Colin
06-02-2010, 09:47 AM
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RE: os f plug
"F" plug works great in my .55AX
...... stopped the unexpected flameouts that mine and many others have experienced. Do a search and you will find a lot on this.
...... stopped the unexpected flameouts that mine and many others have experienced. Do a search and you will find a lot on this.
06-02-2010, 10:36 AM
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RE: os f plug
ORIGINAL: Crash Campbell
(if my maths is correct) are exactly half those of a two stroke.
Cheers,
Colin
(if my maths is correct) are exactly half those of a two stroke
.Cheers,
Colin
I did some research and used my calculator... twice.. you are correct.
06-02-2010, 05:04 PM
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RE: os f plug
ORIGINAL: exeter_acres
I did some research and used my calculator... twice.. you are correct.
ORIGINAL: Crash Campbell
(if my maths is correct) are exactly half those of a two stroke.
Cheers,
Colin
(if my maths is correct) are exactly half those of a two stroke
.Cheers,
Colin
I did some research and used my calculator... twice.. you are correct.
It doesn't happen very often. Just ask my wife.
Cheers,
Colin
06-26-2010, 12:21 AM
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RE: os f plug
It's a mystery why OS plugs like the #8 have such short threads. There are ample threads in the head for a true long reach plug. In theory a hot plug like the F will advance the combustion timing slightly and/or require a slightly richer needle setting to offset that. If you are having flameouts though due to the plug getting wet with an inverted mounting position, the F plug makes more sense than using an idle bar plug which will cost you a few hundred rpm on the top end.
Ernie
Ernie
