Timing Marks John Deere 1020

ACBK1

New User
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.
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With the engine running at full throttle use a timing light to set the timing with the S lined up with the pointer. At 2100 rpms your distributor is fully advanced so timing will be ok even though you aren't running quite up to speed. The 1,2,and 3 have to do with adjusting the valves. Check your throttle linkage adjustment then set the stop screws on the lower end of the throttle lever shaft in the battery box.
 
Thank you very much for the info. Right now at 2100rpms timing light connected to #1 plug wire reads #1 not the "S" mark so that is good to know that the distributor is fully advanced and I can time it to the "S" mark at that speed or higher. Do you think that will eliminate the blow back through the oil bath air cleaner when I accelerate or could that be something else?

I'll see if I can adjust the high end throttle stop as well.

Thanks again!
 
I'm not trying to steal this thread, but are the timing marks on a 301A industrial that same as a 1020? My tractor and manual are 100 miles away, but I recall the service manual just said to align the mark on the crankshaft pulley with the mark on the block. I recall seeing multiple marks on the crankshaft pulley, but don't remember what they were.
 
do yourself a favor and get rid of those points, put in electronic kit. Also be sure those valves are properly adjusted, carburetor clean, fuel filters and lines clean. I would run a compression check first thing. Changing oil would be also recommended. Sounds like a maintence condition but the electronic kit around $200 will get rid of any slop caused problems with the distributor. Good luck.
 
While the timing light is hooked up also watch it as you slow the engine down and make sure the advance is working.
 
ET - Thanks again for the previous information on the distributor being fully advanced at 2100RPM. Set the timing last night to the "S" mark on the crank pulley and the engine runs great (better than it ever has). No more blow back out of the oil bath air cleaner, no stumbling and no more backfiring. Only had to turn the distributor a few degrees to move from the #1 mark on the crank pulley to the "S" mark. Still need to check the advance as noted by Mike M's reply in this thread.

Have a great week.
 
Thanks Machineryman. In searching for the issue early on (which ended up being the distributor) I replaced the fuel filter, fuel pump, sent the carb in and had it rebuilt, cleaned the fuel line screen at inlet to carb, replaced the distibutor cap (thinking it might have a hairline crack in it), put a new ignition coil in, and ultimately installed a rebuilt distributor since the shaft bearings in my old one had gotten sloppy. All done in the past 3-4 weeks. Carb definitely needed to be re-built. Oil and hydraulic fluid have less than 10 hours on them. Runs great now that I have timing correct (set last night). But I do need to get the valves checked and adjusted and the compression checked when I get a chance. Also for now I am good but will keep that electronic kit in mind if I have any issues.

Thanks again.
 

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