Not sure where to put this but here goes...
Brand new Jiffy 3hp stx...Only had it for a few weeks...
Only about 100 holes drilled (one tank)
This turkey has always been difficult to start. It simply won't start unless I hold the throttle wide open. That hasn't been a big deal but still doesn't seem right.
But now it's running rough at full throttle, basically it idles fine, when I just open the gas it wants to die. If I feather the gas until wide open it will run good for about 1 to 3 seconds then it wants to die.
If I feather the gas again I can get the blades spinning fine for another few seconds. It was a pain to get just 2 holes drilled today.
I got it home and dumped the gas and replaced with fresh. Checked the plug and it was a nice chocolate brown. I fired it up without the auger attached and held it wide open. It would run wide open as long as I held it but it would surge. I could watch the throttle body pulsing from wide open to about 3/4 open. Similar to an engine in 'limp mode' or somehow governed. It would surge at a rate of about once per second as if I was doing it with the throttle lever myself but I was just holding it wide open.
I noticed 2 small red plastic screws. I assume those were the idle adjustments. There is only about 120 degrees of rotation available. The left screw seemed to adjust the low idle. When turned all the way clockwise it wanted to die, but all the way the other direction it idled fine. At full throttle in my garage without the auger attached, adjusting the right hand screw seemed to have no affect on how high the motor would run and had zero affect on the 'pulsing' or 'surging'.
Any ideas ?....And yes, the vent cap was open on the gas tank..