I have a John Deere 1020 (RU style / 3 cyl gas / serial No. 053418 - Yr. 1967 I think) and am trying to find out what the 1,2,3 marks on the crankshaft pulley are for. Manual only covers the "S" mark.
It started running rough and then backfired once in a while. I thought it was a fuel problem but finally discovered it was the distributor shaft bearing or bushing that was wearing out. It was allowing the distributor shaft to wobble slightly as evidenced inside the distributor cap which had gouges in the plug wire terminals from the rotor. So I ordered a rebuilt distributor, set the point gap, got it installed and at least started.
In trying to get the timing set correctly, I can only get the tractor up to PTO speed at around 2100RPM (May be too much play in my throttle linkage or govenor). The manual says set timing so "S" mark on crankshaft pulley lines up with the timing mark on engine block at 2500RPM. There are 3 other marks at 3rd points on the crank pulley that have a 1, 2, and 3 stamped next to them. I assume those mean cylinder 1,2,3. The "S" mark is about 3 or so inches counterclockwise from the #1 Mark (between #1 & #3 Marks). Right now the timing is set where the #1 mark on the crank pulley lines up with the engine block timing mark. It runs pretty good but has to turn over more than it used to to start and backfires once in a while after I shut it off. Also when I tap the throttle to speed up it sometimes blows a single puff of oil spray out of the top of the oil bath air cleaner intake.
My goal is to get some help to hold the throttle at the carburator at 2500RPM's while I time the distributor to the "S" mark. But does anyone know what the purpose of the 1,2,3 marks are on the pulley? The service manual does not cover those markings at all. Maybe they line up with the timing mark on the engine block when the timing light lead is attached to the corresponding cylinder plug wire no matter what the RPM's? Or the "S" mark is an advance setting for #1 cylinder when the engine is at 2500RPM?
If anyone knows the purpose of those 1,2,3 marks please let me know and if the oil bath blow-back might be a timing issue (Photo of pulley markings attached). Hopefully this weekend I can get it up to 2500 rpms and time it to the "S" mark and see if it runs better.
Thanks in advance for any input.
It started running rough and then backfired once in a while. I thought it was a fuel problem but finally discovered it was the distributor shaft bearing or bushing that was wearing out. It was allowing the distributor shaft to wobble slightly as evidenced inside the distributor cap which had gouges in the plug wire terminals from the rotor. So I ordered a rebuilt distributor, set the point gap, got it installed and at least started.
In trying to get the timing set correctly, I can only get the tractor up to PTO speed at around 2100RPM (May be too much play in my throttle linkage or govenor). The manual says set timing so "S" mark on crankshaft pulley lines up with the timing mark on engine block at 2500RPM. There are 3 other marks at 3rd points on the crank pulley that have a 1, 2, and 3 stamped next to them. I assume those mean cylinder 1,2,3. The "S" mark is about 3 or so inches counterclockwise from the #1 Mark (between #1 & #3 Marks). Right now the timing is set where the #1 mark on the crank pulley lines up with the engine block timing mark. It runs pretty good but has to turn over more than it used to to start and backfires once in a while after I shut it off. Also when I tap the throttle to speed up it sometimes blows a single puff of oil spray out of the top of the oil bath air cleaner intake.
My goal is to get some help to hold the throttle at the carburator at 2500RPM's while I time the distributor to the "S" mark. But does anyone know what the purpose of the 1,2,3 marks are on the pulley? The service manual does not cover those markings at all. Maybe they line up with the timing mark on the engine block when the timing light lead is attached to the corresponding cylinder plug wire no matter what the RPM's? Or the "S" mark is an advance setting for #1 cylinder when the engine is at 2500RPM?
If anyone knows the purpose of those 1,2,3 marks please let me know and if the oil bath blow-back might be a timing issue (Photo of pulley markings attached). Hopefully this weekend I can get it up to 2500 rpms and time it to the "S" mark and see if it runs better.
Thanks in advance for any input.