I've had this old 038 sitting in the basement for a couple years waiting for time to work on it. Finally got a chance to mess with it and found that it would take a long time to drop to idle and sometimes wouldn't at all. I turned it various ways and the idle would fluctuate big time. It also was weak in the cut during full throttle. I pulled the muffler thinking scored piston. However the compression was great and the piston looked like new with no scoring. The intake side of the cylinder also was smooth as silk.
The weird idle got me on the seals hunt. I pulled the flywheel and clutch and checked both crank seals. Both were fine and with no bubbling soap with pressure applied. The impulse line was fine. The intake boot looked ok as well.
All this time I had assumed the throttle worked as it should. I watched it after I put the carb back on and could see that the shutoff switch spring tension on the lever was holding the throttle from closing all the way at times. I squeezed a little tension out of the kill switch spring and it now will idle! LESSON LEARNED... bad idle or fluctuation based on saw tilt doesn't always equal bad seals. Check the throttle butterfly first and make sure it's closing.
Next... the saw would run but run low on power in the cut. Eventually it would start and stall. I figured hole in the fuel supply line. It was fine. The fuel filter screen looked clean and as good as new... but I filled the filter with water and it held it. The screen looked clean but was varnished solid. I scratched it with a utility blade and ran water pressure through it. Now the saw runs like a top and with plenty of power.
The main lessons here are just because the filter looks clean (Same with carb screens), always check. I've found many clean screens that hold water. This means no fuel. Also, weird idle issues that can't be adjusted or fluctuate aren't always the seals (crank, carb intake boot, impulse line, crankcase seals). Check the simple things first.
The weird idle got me on the seals hunt. I pulled the flywheel and clutch and checked both crank seals. Both were fine and with no bubbling soap with pressure applied. The impulse line was fine. The intake boot looked ok as well.
All this time I had assumed the throttle worked as it should. I watched it after I put the carb back on and could see that the shutoff switch spring tension on the lever was holding the throttle from closing all the way at times. I squeezed a little tension out of the kill switch spring and it now will idle! LESSON LEARNED... bad idle or fluctuation based on saw tilt doesn't always equal bad seals. Check the throttle butterfly first and make sure it's closing.
Next... the saw would run but run low on power in the cut. Eventually it would start and stall. I figured hole in the fuel supply line. It was fine. The fuel filter screen looked clean and as good as new... but I filled the filter with water and it held it. The screen looked clean but was varnished solid. I scratched it with a utility blade and ran water pressure through it. Now the saw runs like a top and with plenty of power.
The main lessons here are just because the filter looks clean (Same with carb screens), always check. I've found many clean screens that hold water. This means no fuel. Also, weird idle issues that can't be adjusted or fluctuate aren't always the seals (crank, carb intake boot, impulse line, crankcase seals). Check the simple things first.
