Saw chain seem to be low profile will other brand chain fit my poulan 20

I am pretty sure this machine ran a .325 pitch chain, so the file size is 3/16, if it is running 3/8 low profile chain ( 91 ) it will be a 5/32 file, the pitch should be marked on the bar .

If it has 3/8 low profile chain as most machines do it will be a 5/32 file.

3/8 low profile chain requires a 7/32 file

It realy depends on the type of chain you have fitted, hobby chain fitted to small home owner saws is normally a 3/8 low profile and requires a 5/32 file, slightly bigger machines have a .325 chain and require a 3/16 file, big machines have a standard 3/8 chain and require a 7/32 file, the correct file should fit nicly into the cutter and sit slightly abobe, this will stop you file under the cutter head and creating a hook.

yes it can also try lock washers on the old one

Poulan "1420 Electric Saw Type 2" (may not be your saw)http://www.ordertree.com/modelinfo/PWE/1420-Electric-Saw-Type-2/75.1420-Electric-Saw-Type-2.1.59.1.html
Open the link; Click "View the illustrated parts list [GO]" link; open the "Illustrated Parts Lists" folder; Click "Chain Saw Assembly Type 2". Compare items 20 and 21 with your saw, the flared portion of 20 should be toward the clutch cover not the engine and on the clutch side of the bar. The only other thing that comes to mind is item 23 should fit into the hole on the bar (the bar should be tight against the oiler channel; engine side of the case.). HTH
Lou
If these are correct please add comments below and we will continue.

GS, there is a pump driven by the clutch sprocket/drum. Operate the engine with the bar off. There should be oil coming out.

a) If so, the hole in the bar is plugged with saw dust. This is very common on all brands of saws.

b) If not, then remove the clutch/drum assembly and inspect the worm gear drive of the pump.
*note, the threads on all chain saw clutches are Left Hand reverse threads.

I’m happy to assist further over the phone at https://www.6ya.com/expert/rolandw_c013176d62ee17ae

I got 1 hit for your filter, if you haven' already give them a try "Poulan air filter 530023046"
http://www.lawnmowerpros.com/Poulan-Parts-Search.asp
Lou

the chain on these saws will only go in one direction ~ when you re-move the sheild to fit the chain a small diagram will be shown to what direction is required.
if this is not the problem and the teeth won't fit any where on bar then check for damage to bar or dirt stuck in it.clean out with soapy water and use spay oil to prevent rust.

you need to adjust the gas an air on those two little screws on the carburator