371xp IDLE PROBLEM

[nickoftime]

My 371xp was leaning out halfway into big cuts but would idle fine and throttle response was great.I replaced carb diaphrams ,filter and fuel lines ,then setup the mixture screws to get good idle, crisp response and a little bit of 4 cycling with no load. After a minuite the mixture seems to be a bit rich down low and idle slows and it stalls a lot. I stall it a lot after idling when I tip the nose of the saw down. If I lean down the low speed any , it will not come back to idle after a cut and chain keeps running. Saw has low hours and tons of power while cutting.

 

[HiOctane]

Can you check if the carb can hold 6-7 lbs of pressure?Did you adjust your inlet lever correctly,flush to body ?Sure the plugs are not leaking ?Another thing,check if it makes difference running the saw without air filter,it could be clogged and make your saw running rich.

 

[funky sawman]

Main nozzle in the carb is bad---Replace the carb. I go threw about 1 carb a month on 371/372 saws. The new carb is the walbro hd12b. These walbros are very touchy with ethanol that causes the nozzle disc to not seal fully at idle.

 

[nickoftime]

Thanks for quick replies. I havent done the pressure test before . Do i simply apply pressure to the fuel inlet and wait to see if it bleeds away ? Also I am not sure what the "nozzle" is which goes bad in these carbs a lot. I think it must be somthing in the bore between the choke and the throttle.
One more thing: the 371 has been flooded most times when i first start it cold and will only fire with full throttle.

 

[ironman_gq]

did you warm the engine up fully before you tuned the carb. a cold engine will need more fuel to run properly then a warm one so a warm engine will run rich if you tuned it cold. IT may take a little longer for your saw to warm up and run smooth when you start it in the morning but if its tuned right it will run much better the rest of the day

 

[nickoftime]

I have been warming up saw for 2 or 3 min then tune . I find that it is easy to get it perfect . Then after 5 min of use or less the stalling starts and i try to retune but its very fussy on the low end .It goes from fat to lean with very little movement on the screw.

 

[howellhandmade]

Watching this with interest, my MS361 does exactly the same thing. Is fine in the cut, but idle is finicky -- either stalling out or spinning the chain, hard to keep in the sweet spot.

Jack

 

[ironman_gq]

2 to 3 minutes with no load on the saw (cutting) is not enough time to get them fully warmed up. I like to make a nice long cut down the length of a log to put a decent load on the saw and get it warmed up (learned it from my dealer who has been selling and fixing saws for a long time) then tune em. If its stalling while cutting it could also be a plugged tank vent causing a lack of fuel