Chainsaw runs full speed when first starting and won't idle. Just dies

[czombie]

Okay I don't know what is going on with my Poulan Pro 50cc. It has been running perfectly (last 2-3 yrs) up until today. Ran fine just a couple of days ago. BUT today I was cutting up some limbs when out of the blue it just suddenly revved up to full speed while I was moving limbs out of the way. Ever since that moment it is sporadic it how it runs. It will just run full speed right after it starts and once I can get it to settle I have to throttle it to keep it running. Also it is now hard to start. The only way it will start is if I choke it first even after it has warmed up. Before today it would run, idle, and start perfectly even after hrs of hard use.

I've checked everything....All filters are/were clean before using today. No cracked fuel lines, etc. I even ran it dry and made up a new batch of gas and it is still running the same. Spark plug is clean (not oily/wet, etc).

Carb need to be broken down and checked...??

 

[old-cat]

You suddenly got an air leak. Something likely came apart. I don't know Poulan saws, so I'm not much help.

 

[fearofpavement]

I concur. Bad air leak. Check the security of your carb attachment. If there is a boot or plate between the cylinder and carb, check that on both ends.

 

[Trip660]

You should also check to see if all the cylinder base bolts are still tight. Once had the same thing going on, turned out that two of the four bolts had vibrated loose and part of the base gasket got sucked into the crankcase creating a massive air leak.

 

[czombie]

Ok....thank yall for the replies. I'll check it out tomorrow.

 

[czombie]

my local pawn shop has a clean running shindaiwa 488 for 50 bucs I may just have to go pick up tomorrow....just in case...lol

 

[stubnail67]

Okay I don't know what is going on with my Poulan Pro 50cc. It has been running perfectly (last 2-3 yrs) up until today. Ran fine just a couple of days ago. BUT today I was cutting up some limbs when out of the blue it just suddenly revved up to full speed while I was moving limbs out of the way. Ever since that moment it is sporadic it how it runs. It will just run full speed right after it starts and once I can get it to settle I have to throttle it to keep it running. Also it is now hard to start. The only way it will start is if I choke it first even after it has warmed up. Before today it would run, idle, and start perfectly even after hrs of hard use.

I've checked everything....All filters are/were clean before using today. No cracked fuel lines, etc. I even ran it dry and made up a new batch of gas and it is still running the same. Spark plug is clean (not oily/wet, etc).

Carb need to be broken down and checked...??

i would check piston also for light scoring....

 

[rattler362]

I would take a look at the fuel line.

 

[Marshy]

Sounds like an air leak possibly, might be a crank seal and burnt down already. Post a picture of the plug color for us and do a compression check and post numbers.

 

[czombie]

Well she's back to running and purring like a kitten. Simple air leak was all it was. Carb nuts were completely loose (backed off) and sucking loads of air. She put in another 3-4 hours of good use today and didn't skip a beat.

Thx for all the help guys.

 

[Marshy]

Lucky dog, you could have melted it down if you kept running it. Good save.

 

[czombie]

Lucky dog, you could have melted it down if you kept running it. Good save.

I should have known better than to completely over look the air leak ...I'm glad I came here as yall helped me save my saw.

thx again yall.

 

[dt77]

Did I burn up my saw? Poulan pro 42cc. Took down a big maple, cut everything up fine. . .another day it started up well and instantly revved full...pulled the trigger and it died. Plug was almost whitish/silver. So far have changed the plug, ignition coil, carb, filters. Won't ignite...not the slightest attempt to spark...I'm confused...any ideas?

 

[Bob Hedgecutter]

Did I burn up my saw? Poulan pro 42cc. Took down a big maple, cut everything up fine. . .another day it started up well and instantly revved full...pulled the trigger and it died. Plug was almost whitish/silver. So far have changed the plug, ignition coil, carb, filters. Won't ignite...not the slightest attempt to spark...I'm confused...any ideas?

Yes- start a new thread about it instead of digging up and tagging on to one near a decade old.
Most likely your saw is fried and you replaced parts that did not need replacing- take off the muffler and take a photo of the piston as viewed through the now exposed exhaust port of the cylinder.