I am slightly confused

[jimmorrison]

XS372xp, recently acquired, great saw. 5 tanks through, runs and cuts great. I'm cleaning up a dead fall, working until dark. Put everything away, and go back at it in the morning. Total user error, never prepped, didn't check, just went to start saw. It wouldn't start, I pulled a few more times. Duh, tank was empty. My only experience with this saw cold, pops on first pull, shut off choke, starts on second pull. Warm or hot start, hold throttle open, starts on first pull. After realizing my mistake, I fueled the saw and tried to start it. Popped on the first pull and wouldn't start after. I pulled a few more times. It was flooded. I set it aside, and used a different saw. After sitting in the sun and wind for a couple of hours, popped on first pull and flooded on second. I pulled the plug, it was wet. Dried it off with a small butane torch, this always works. Popped on first pull, flooded on second. WTH? I swapped the plug, same thing. If you run a tank out, and suck some water or sludge into filter, shouldn't the saw be starved for fuel? It wasn't starved, it was flooded, the plug was wet. I let the saw sit overnight, replaced the in tank fuel filter, popped on first pull, started on second. I used it all day, ran great. What am I missing?

By the way, thanks to mncutter and Kevin, nice saw.

 

[huskihl]

Glad you like your saw.

Did you accidentally leave the choke lever out?

If not, the only other way fuel gets through the system is through the metering needle in the carburetor, or possibly back through the impulse system into the crankcase if the fuel pump diaphragm is bad. Something is holding the needle away from the seat. Either crud underneath the needle or maybe a stiff or torn diaphragm

 

[jimmorrison]

I left the choke lever out on my first attempt, after refueling. I figured the saw was starved for fuel because I continued pulling with an empty tank. On subsequent attempts, the saw popped on first pull, so I shut the choke off.

 

[hacskaroly]

I left the choke lever out on my first attempt, after refueling. I figured the saw was starved for fuel because I continued pulling with an empty tank. On subsequent attempts, the saw popped on first pull, so I shut the choke off.

I find that if you run the saw empty, refuel and then restart, if the saw is still hot/warm then using the choke will result in the saw flooding. Setting the saw to full throttle or idle and restart should be all you need. It may take an extra pull or two to get the new fuel pumped through the lines, but won't flood the saw.

If you realize you flooded the saw, just put the throttle setting to full throttle (no choke) and give it about 20-30 pulls, it will clear at some point along the way, start to sputter and then run. This allows you to use the saw sooner instead of letting it sit and naturally air out.

 

[jimmorrison]

I'm wondering if I just misdiagnosed what was happening. Is it possible the fuel was restricted enough to prevent starting, but not enough to get the sparkplug wet? Why did it immediately sound like it was flooded, on the second pull, with the choke off? Either way, replacing the filter is what worked. Saw popped on first pull and started on second.

 

[Wilhelm]

The/my PS-6400/7300/7310/7900 are notorious for doing this.

Once they pull fumes into the carb they won't start due to fuel starvation at first, then they flood for no apparent reason.
Also, they flood easily on first cold start pull which is why I implement a first "no choke no throttle" pull and many times they will actually pop - if choke had been engaged they'd have flooded.

Once they flood it is best to let them sit over night and they will cold start normally the next day.
Although, as @hacskaroly wrote, I did find that they can and will pop/start even miserably drowned if I engage full throttle no choke and keep pulling.
Certainly not a procedure healthy for a 2-stroke engine, but in a pinch...

I no longer pull plugs on flooded saws unless I can't turn the engine over due to hydro lock.

My best guess is the sucked in fumes interfere with proper operation of the carb (vapor lock) and since gasses are compressible it is difficult to get them out of the carb.

 

[cuinrearview]

Some pulls with fast idle engaged might get you going. If not, set the bar tip on some wood, hold the throttle wfo with your right hand, and yank on the starter rope with your left until it takes off.

 

[Duane(Pa)]

Zip tie that throttle wide open (very dangerous) unless you can man handle it and yank while holding trigger. Probably smoke show until you burn residual fuel out of crankcase.


ETA I see Tim gave solid advice above