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John Deere 40 Wont Start

A

Anthony G

New User
Have had the tractor since March. Has had no problem starting
until battery wore out. New battery started on first pull, with no
choke usual. Throttle at half open. Let tractor sit for 2 weeks and
wont start at all. Engine turns over fine, battery seems strong.
Only occasionally would I hear a pop from a cylinder. Not sure if
it was a power stroke or if it was just the sound of the gases
being compressed. Started to investigate. No obvious problems
with fuel system. Carberator is getting fresh, clean gas. And I
drained it a few times to see if it was flooded. Still wont work.
Then went to investigating the throttle. It was found that the
linkage of the speed control lever had been "modified" so that
basically the lever on the carb was always fully open. Not sure
why this was. Adjusted governor lever, speed control lever, and
carb lever so they were all proper per service manual. Still wont
start. Investigated the distributor and all wires. All seem intact
and fine. Distributor seems fine. Repeated attempts to start the
motor resulted in what I believe to be a dead battery or a ruined
starter motor. Now nothing happens when I pill the starter
linkage. I have no battery tester or charger. Will buy one.
Removed spark plugs, they seem old. Any ideas?
 
(quoted from post at 09:51:50 08/01/14) Have had the tractor since March. Has had no problem starting
until battery wore out. New battery started on first pull, with no
choke usual. Throttle at half open. Let tractor sit for 2 weeks and
wont start at all. Engine turns over fine, battery seems strong.
Only occasionally would I hear a pop from a cylinder. Not sure if
it was a power stroke or if it was just the sound of the gases
being compressed. Started to investigate. No obvious problems
with fuel system. Carberator is getting fresh, clean gas. And I
drained it a few times to see if it was flooded. Still wont work.
Then went to investigating the throttle. It was found that the
linkage of the speed control lever had been "modified" so that
basically the lever on the carb was always fully open. Not sure
why this was. Adjusted governor lever, speed control lever, and
carb lever so they were all proper per service manual. Still wont
start. Investigated the distributor and all wires. All seem intact
and fine. Distributor seems fine. Repeated attempts to start the
motor resulted in what I believe to be a dead battery or a ruined
starter motor. Now nothing happens when I pill the starter
linkage. I have no battery tester or charger. Will buy one.
Removed spark plugs, they seem old. Any ideas?
Click to expand...

Let's start with you telling us what the tractor is. I don't hear you mentioning spark at all. Is it getting spark at the end of the wires , nearest to the spark plugs. You must have gasoline and spark. There are many people on here who are familiar with a variety of tractor and they will gladly help. Provide us with more info and we will see if we can help. Farmalls are my specialty.
 
Always start with the most obvious: spark

If not spark clean your points - and you're probably good to go.

If there is a strong spark to all cylinders - then look at the carb.

Try starter fluid - if it fires you most likely have a carb problem.

If not - then things get deeper.

Check your compression. If one cylinder's real low - assume a stuck valve.
 
(quoted from post at 10:19:13 08/01/14) Always start with the most obvious: spark

If not spark clean your points - and you're probably good to go.

If there is a strong spark to all cylinders - then look at the carb.

Try starter fluid - if it fires you most likely have a carb problem.

If not - then things get deeper.

Check your compression. If one cylinder's real low - assume a stuck valve.
Click to expand...

Sorry I mised the fact that it was a JD 40. I agree with JR Sutton.
 
Does your 40 have an hour meter? Or maybe had one at one time?
If so check the fuse that is behind the panel where the temp and amp gauges are located or just above the voltage regulator.
just a thought.
Steve
 
actually I reread your post more completely and see you're dead in the water.

If it were me in that position - and needed the tractor to start - I'd guess it's the points, clean them - then try pull starting the tractor. Either with another tractor or a car/truck. If car/truck - be sure the person pulling understands the limits of a tractor!
 
You did turn the switch on didn't you ? BTDT

Next check for power to the coil to see if the switch even works.

Then test for spark.
 
First, get some power back into the battery. Let it charge on slow (5-10 amps) overnight if possible.

Get the new plugs, but before putting them in connect the wires and lay the plugs on a metal surface, facing where you can see the electrode end, crank the engine over and see if there is spark.

If no spark, check the points, voltage to the coil, and cap and rotor . You must have spark at the plug, not just at the coil.

If the engine will not crank over, as in no starter cranking, start checking for power to the starter and starter solenoid when the switch is in start position. If there is power to the starter, and power to the solenoid, and you know the battery is charged, the starter may have failed.

Just for future thoughts... Not being mean to you, but tackle the problems one at a time. The throttle linkage had to have been wrong before the starting problem, after all it WAS running that way.

Next time, get it running first, then work out the other problems, one at a time. Then you know what worked, what didn't, or what needs to be put back like it was!

Let us know how it goes!
 
The butterfly in the cab should be open if the engine is not running regardless of where your hand throttle is positioned. When the engine starts it spools up to the point where the hand throttle is positioned and then the governor pulls the linkage to keep it there. Your throttle lever is only indirectly linked to the carb.

If you set all of that with the factory service manual then it can't be your issue. I'd go with points needing attention and/or new plugs. More than once I have seen a tractor not start because the engine got flooded and the spark plugs wouldn't fire after that.
 
Clean the points and check that the condenser screw is tight. Also check wires inside the distributor for tightness & that they are not touching metal.
Spray some brake cleaner in the cap to help remove conductive moisture and completely dry the inside of the cap and the rotor.
Condensers seem to fail more rapidly these days (cheap imports) so an American made replacement might help. Check NAPA.
 
Ok. So I got some new plugs and charged the battery. Starts right up w/out choke.

Since I messed with the governor/carb/control lever linkages I noticed 1) that the engine is running a bit smoother and faster
2) that the idle can go so slow that the engine is almost stopping 3) that the little butterfly lever (lever F in the JD Service manual) is going trough a greater range of motion than before, however, not its complete range of motion

Also, one bad thing seems to be that it makes some black smoke, which it didn't before.

Figuring that the black smoke was too rich of a fuel-air mixture, I adjusted the carb needle in (clockwise) expecting I would eventually starve the engine and it would stall. I turns out that I screwed the needle in until it would go no further with a goodly amount of torque from a screwdriver and it still produced black smoke (not a whole lot, but more than before, when it only made black smoke briefly when choke-started). Does this mean I should replace the little parts inside the carb (I bought a kit to do this)? Should I mess around the the relationship between the control lever, carb lever, and the governor control arm more?

Thanks in advance.
 
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