Pinched line? Weird running problems!

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Brent Nowell

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Was milling with the 3120xp and noticed she started to run lean after the 7th cut.
Idle was erratic and I couldn’t get it to stay steady and it would go from high rpms to nothing and then just randomly stall. So instead of chance any more damage than I may have possibly done, I packed it up.

got home and tore her right down to the piston, had some minor scratches on the exhaust side of cylinder at the very bottom.Red engine paint on the muffler had burned off and it’s good for 470f so I knew things where def getting hot.
Checked squish, removed base gasket and used Honda bond for sealant. Next day I did a pressure and vac test at 10” vac and 10psi and she held.
Put it all back together and fired it up and erratic idle again, tuning the L jet to rich, then lean and adjusting idle and just can’t get it to idle consistently. Saw will idle high and then just die!
So I finally realized near the end of this 20 minute tuning session that when I press down on the top of the saw, it will sputter and die, but if I don’t put any pressure on the top of the saw it will idle high. When pressure is applied I noticed quite a bit of smoke coming out the muffler before it dies indicating that putting pressure on the saw allows more fuel to come in.

I figured a pinched line and used some needle nose to pull the line out of the tank some and found that the line seemed to be pinched at the point where it entered the tank.

muse anyone experienced this before? The line is so rubbery I feel like it could get pinched very easily and I’m thinking of replacing it with the clear yellow stuff.
Opinions comments more than welcome here!
 
Found what looks like that the fuel line was not pulled out from the tank far enough... causing too sharp of a bend. Threw pressure and vacuum on the line and no problem... put an o-ring on the nipple to the carb kinda like a clamp to eliminate any possible air leak there..
I’ll have to try and tune it again, surprised no one has seen this kind of issue before, which makes me think I’m probably on the wrong track
 
Found what looks like that the fuel line was not pulled out from the tank far enough... causing too sharp of a bend. Threw pressure and vacuum on the line and no problem... put an o-ring on the nipple to the carb kinda like a clamp to eliminate any possible air leak there..
I’ll have to try and tune it again, surprised no one has seen this kind of issue before, which makes me think I’m probably on the wrong track
I have seen it before, as said fuel line gets pinched between carb plate and fuel tank. Would have to be sharply pinched to hold vacuum or pressure.
 
Update

seems it was a pinched line. Finally had the time to fire it up and tune it, getting a steady idle now with the normal variations in speed instead of what I saw before.
I also pressed down on the saw multiple times and it did not stall.
line was pulled to far up to the carb inside the air filter box. Need to leave a nice curve of line between the tank and the air box or it starves the engine of fuel.
 

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