When you changed the carb, did you install a new intake gasket? Also, did you replace the fuel line and wash out the fuel tank? When you say it runs for a short period, how long, a few seconds or a few minutes? Will it rev with the throttle or is there no change in engine speed? Also, what model Poulan is it and do you have the numbers and name from the carburetor? Thanks, PK.
no did not replace intake gasket-new fuel lines installed with new carb-walbro-hda-49
flushed tank with carb cleaner. after installing new carb it started on first pull -ran for about 45 seconds and would rev up nicely -then acted like it ran out of fuel.would not restart right away-after about 30 minutes i tried again it started and ran about 15 seconds then quit.poulan 3500-3.7 c.i.
There are several things that could be wrong so let's start with the simplest and obvious. Fuel lines in the right place. The filtered line has to be on the intake side of the carb. Try running it with the fuel cap loose. If that fixes things then the cap is bad or the tank vent, whichever way it's set up. The exhaust could be plugged up. Pull the spark arrestor and make sure it's clean. There may be an excess of carbon build-up in the combustion chamber. There are chemicals you can use to clean that, but this should be a last resort. There's a chance the ignition module could be bad, they can be maddeningly difficult to diagnose. The jetting could be out of adjustment, you need to get it to idle well using the slow speed jet then adjust the high speed jet. The carb adapter could be faulty or the clamp might not be applying even pressure, but the engine would likely run rough it this was it although it could rev up quickly and then shut off.
I would be inclined to think it's a fuel delivery problem myself. Probably a venting problem would be what I'd be trying to chase down. Next I would verify that the ignition is firing properly. After the engine shuts down, quickly check that it still has fire. If it isn't firing, check the on/off switch. Hope this helps. If you still have trouble, come back and tell me your results and findings and we'll try something else. Thanks, PK.
thanks p.k.-it will be probably be next weekend before i can get back with you-iwill keep you posted-thanks again