I have alot to learn about trouble shooting saw problems as well as carb problems[/
I have found most problems that happen is because the previous owner left fuel in the saw and just tossed it in the shed to be used in a year or two. With that in mind figure on new fuel lines, new impulse line(if it uses one, some don’t) and a carburetor kit. The pump diaphragm in the carb has to be soft, supple and flexible. If you take the diaphragm out and it’s kind of hard and crinkly it won’t pump fuel. Crankshaft seals are often overlooked in learning how to diagnose. As a rule of thumb start with 2 turns out on the high and low speed adjustments. I picked up a Stihl 039 one time that wouldn’t idle correctly unless the adjustments were about 4 turns out out and it’s idle was really high. I found that the clutch side crank seal was bad because the bearing was bad which tore the seal which created a vacuum leak.
3 things required for an engine to run.
You’ve got to have fuel/air.
You’ve got to have spark.
You’ve got to have enough compression. Take any one of those away and it won’t run. One of the first things I do is pull the engine over. With enough experience you’ll know if the compression is good enough to run. Then I check for spark. Then dribble a little fuel into the carb and see if it’ll start. If you have the first two, it’ll start. Then check the fuel lines. That will tell you pretty much where to start repairs.
From what I’ve seen, saw manufacturers started switching to electronic ignition in the late 70’s to 80’s.
So if there’s no spark just figure a new coil. Coil to flywheel gap just use a business card to set the gap. It’s close enough. Always use the magnet side to set the coil gap.
It won’t take long to get used to figuring what’s wrong with a saw. But always, always, always start the diagnostic process with a known hood spark plug.
Once, between me and 5 others that are on here, we spent the better part of a day trying to figure out a no spark issue on my Dolmar 510 only to figure out it was a defective new spark plug.
As I’ve said before, it’s just a saw, not the Space Shuttle. It’s not that hard.
I’ll add another new saying to that, too.
If it was made by God, it would be perfect with no problems. But it’s made by man and is problematic at times.
