Just finished up repairing all five of my big saws’ throttle locks. The push buttons were really loose, in & out, with little to no spring pre-tension. A couple of them would stick on high idle until you worked the throttle trigger a couple of times to help free the lock pin up & out.
Why Poulan used an open ended coil spring on those 4200-6900 series saws baffles me. The inner spring coil ends had all spiraled their way down inside the handle, wedged between it & the lock pin shaft.
I made a batch of tiny washers to just fit 0.005” over the shaft, cut the washers ODs down to fit inside the handles spring bore, stretched the return springs out a bit, and then bent the coil ends down with needle nose to be flat ended.
Bought a batch of new midget sized 1/16” diameter by 1/4” long roll pins to replace the old ones I lost during reassembly.
Note that you can’t get the throttle lock pin all the way out of the handle, w/o disassembling the handle/gas tank, & I’m not going there...
If you stuff a slot tip screwdriver down between the lock pins big head & the plastic trigger, you can hold the lock pin in the outermost position, in order to reinstall & align the push button over the shaft & then press in the little roll pin with channel locks.
Poor cell phone pics, note used Brownells gunsmithing spring kit for spring making & a 1/16” roll pin punch from their set.
Support the button with a woodblock or wedge, when you tap the roll pin out, because the lock pin is fragile. Took pics from a handle off sample, but you can do this w/o removing the carb or linkage or trigger, just the top cover needs to come off.
I couldn’t get the new custom washer pulled back out for a pic, but you see the shiny washer down in the handle bore.
Don’t cut a spring too long, if you make a new one, because if the solid height is too long, it will not allow the pin head to catch the throttle trigger on the back side....0.024” wire at 5 coils did the job for replacements. Stretch the spring to just give some pressure outwards when the
button is installed over the shaft & the pin holes are aligned, trial & error.
Realign the button hole to the shaft hole with your punch, hold in slightly with your thumb, then start the roll pin in from the other side.
Use pliers to squeeze the roll pin end, rather than hammer it in.