Just thought I needed a project saw with a future of being a loaner saw, so I bought what was listed as an 024 on eBay for $61 plus shipping. If it was a total piece of junk, I could part it out and recoup the purchase price.
The description was:
"1- Used STIHL 024 Power head / No bar or chain
Unit for parts or repair. Low compression , believed to be scored cylinder.
Fairly clean machine, appears to be in decent shape overall."
Indeed the unit looked like an 024, with the lower cylinder cover profile as compared to an 026. Then again the cylinder cover badge was missing. First thing I pulled the spark plug and measured the compression, about 160 psi. Lower than factory new, but still respectable. Next step, off came the muffler to look at the "scored cylinder". A few marks on the piston, but the cylinder wall was perfect. Oddly I could see the top of the piston drop clearly drop below the exhaust port. Out came the digital calipers to measure the bore diameter, it was 44mm and not the 42mm spec for the 024 saws. So at least the saw had a 026 cylinder on it, and I could see the Stihl and 1121 markings on the base of the cylinder so it's clearly an OEM cylinder. Back of my mind I'm wondering if this was a 026 cylinder installed on a saw with an 024 crankshaft, so next I measured the squish. It was a fat .056" or about 1.4mm, while the stroke difference between the 024 and 026 is 2mm. Next I looked for a cylinder base gasket, and it was clearly present, so clearly the saw had a 024 Super or 026 crankshaft. Time to take a look at the top of the cylinder more closely and compare it to an 026. Bingo. Bubba had worked on the saw and to make the cylinder cover fit after the 026 jug was installed he removed a portion of the cooling fins on the top of the cylinder.
Based on the air filter, I'm guessing that this saw was was a 024 Super that had a 026 cylinder installed on it. Just wouldn't have made any sense to the put 024 parts on a 026. Tach tuned the saw and it pulls a 18" bar with a .325" chain at over 14,500 rpm before I added another 1/4 turn on the high needle and dropped it down to about 13,500. The saw still has issues as it idles rough and starts hard. Going to run it for awhile and see if that improves and if not I'll rebuild the carburetor. Time to order a new air filter and plastic parts to make it right.
The description was:
"1- Used STIHL 024 Power head / No bar or chain
Unit for parts or repair. Low compression , believed to be scored cylinder.
Fairly clean machine, appears to be in decent shape overall."
Indeed the unit looked like an 024, with the lower cylinder cover profile as compared to an 026. Then again the cylinder cover badge was missing. First thing I pulled the spark plug and measured the compression, about 160 psi. Lower than factory new, but still respectable. Next step, off came the muffler to look at the "scored cylinder". A few marks on the piston, but the cylinder wall was perfect. Oddly I could see the top of the piston drop clearly drop below the exhaust port. Out came the digital calipers to measure the bore diameter, it was 44mm and not the 42mm spec for the 024 saws. So at least the saw had a 026 cylinder on it, and I could see the Stihl and 1121 markings on the base of the cylinder so it's clearly an OEM cylinder. Back of my mind I'm wondering if this was a 026 cylinder installed on a saw with an 024 crankshaft, so next I measured the squish. It was a fat .056" or about 1.4mm, while the stroke difference between the 024 and 026 is 2mm. Next I looked for a cylinder base gasket, and it was clearly present, so clearly the saw had a 024 Super or 026 crankshaft. Time to take a look at the top of the cylinder more closely and compare it to an 026. Bingo. Bubba had worked on the saw and to make the cylinder cover fit after the 026 jug was installed he removed a portion of the cooling fins on the top of the cylinder.
Based on the air filter, I'm guessing that this saw was was a 024 Super that had a 026 cylinder installed on it. Just wouldn't have made any sense to the put 024 parts on a 026. Tach tuned the saw and it pulls a 18" bar with a .325" chain at over 14,500 rpm before I added another 1/4 turn on the high needle and dropped it down to about 13,500. The saw still has issues as it idles rough and starts hard. Going to run it for awhile and see if that improves and if not I'll rebuild the carburetor. Time to order a new air filter and plastic parts to make it right.