FlyingGiants Forums - View Single Post

CRUISER · 11-03-2008, 02:23 PM

Mfuess,
I have read most of the pages here and have seen "No Where" any referance to the setting of pop off ! I have recently found issue with an eng i purchased used. It ran faily well but required the needles to be twisted out too far, and the high end was off the spring and i nearly lost it. I have a homemade pop gauge setup so i checked it using syringe and load of fuel for wet pop reading. it was over 18.5 lbs. upon looking at the spring it looked like it had been stretched & clipped till it wasn't much of a spring anymore. I went to the saw shop and they kindly gave me a freebee spring to check. I knew it was too short but it had plenty to work with. I put it in and tested it as is with a reading of 3.5 lbs. I then proceeded to carefully increase the length/tension of spring and testing each time till i got to 11 lbs at which point i stopped. I haven't been able to retune yet as i also had an ignition error and needed to purchase new hall sensor. I've done many serches to find some rule to pop off pressure and only found two bits of info of which one stated he liked 8 lbs and another liked 11/12 lbs pop. neither stated what eng or use but i assumed gocarting. Now i must assume also the the regulation of the fuel is imperitive to the eng's performance and longevity. I would then also have to assume that the pop off is the first step to setting any other adjustments especially the fulcrum lever at needle, barring of course any obvious other problems like air leaks. I read your article and I know it is highly accurate and fully useable but i feel also it might be incomplete, or we are missing another section of it somewhere.
I for one would very much like some clarefication on the popoff and some helpfull guidelines/info so that i might have a fighting chance of getting to that point of having the whole story ! What settings would be best concidered ?

11-03-2008, 02:23 PM	#241 (permalink)
CRUISER Gettin' Lower! Join Date: Aug 2008 Location: Salem, or Posts: 30	Re: Gas engine tuning for newbies.... Mfuess, I have read most of the pages here and have seen "No Where" any referance to the setting of pop off ! I have recently found issue with an eng i purchased used. It ran faily well but required the needles to be twisted out too far, and the high end was off the spring and i nearly lost it. I have a homemade pop gauge setup so i checked it using syringe and load of fuel for wet pop reading. it was over 18.5 lbs. upon looking at the spring it looked like it had been stretched & clipped till it wasn't much of a spring anymore. I went to the saw shop and they kindly gave me a freebee spring to check. I knew it was too short but it had plenty to work with. I put it in and tested it as is with a reading of 3.5 lbs. I then proceeded to carefully increase the length/tension of spring and testing each time till i got to 11 lbs at which point i stopped. I haven't been able to retune yet as i also had an ignition error and needed to purchase new hall sensor. I've done many serches to find some rule to pop off pressure and only found two bits of info of which one stated he liked 8 lbs and another liked 11/12 lbs pop. neither stated what eng or use but i assumed gocarting. Now i must assume also the the regulation of the fuel is imperitive to the eng's performance and longevity. I would then also have to assume that the pop off is the first step to setting any other adjustments especially the fulcrum lever at needle, barring of course any obvious other problems like air leaks. I read your article and I know it is highly accurate and fully useable but i feel also it might be incomplete, or we are missing another section of it somewhere. I for one would very much like some clarefication on the popoff and some helpfull guidelines/info so that i might have a fighting chance of getting to that point of having the whole story ! What settings would be best concidered ?