JD40 new engine but no power

rogersach

Member
Had my JD40 engine totally rebuilt and it starts right away but has no power...I have checked the points, condenser, plugs and coil. Everything is pretty much new even the carb has been sent out and rebuilt. I have set the timing with a light and also adjusted manually to get it as close as possible. The governor is working but not sure it is doing what is suppose to be doing. Any ideas or suggestions would be appreciated.
 
The load adjustment on the bottom of the carb. needs to be opened up more than you would think to pull a load good. It might be that simple ?
 
(quoted from post at 11:59:22 06/21/18) The load adjustment on the bottom of the carb. needs to be opened up more than you would think to pull a load good. It might be that simple ?

When they rebuilt my carb they used a side port for the second adjustment instead of bottom. Could that make a difference?
 
Lets start at square one. Set the throttle and governor linkages first. Then set the timing with a light. At full throttle and on #1 cylinder you should see SPARK in the
center of the timing window. IF your distributor advance is working properly you will see TC / DC near the center of the window at low idle. Tighten down the dist and
leave it alone. When you change points check it again as point gap affects timing. Next move to the carb. At full throttle back out the load screw(bottom) until it starts
to smoke a tad and stumbles. Screw it back in slowly until the engine smooths out. If you want power leave it there. If you are just putting around run it in till it
stumbles and then back out till it just smooths out. To set the idle screw (side near top) drop the engine speed as low as it will go and stay running. Run the idle jet
in or out until it runs fairly smooths. Now listen to your exhaust. If you can detect a gallop in the sound you are good to go. If not reach behind the carb with a stubby
screwdriver and adjust the idle speed. You will have to retweek te idle screw. It's best to do this step the next morning as your hand is gonna get hot. Please post back with an update.
a271155.jpg
 
Roger,
These tractors are pretty simple. If it has gas and spark it should do something. Those are the two things to check. Take plug out of the bottom of the carb and see if gas runs out. Not unheard of the have the needle valve stick shut, especially with the newer style vivtolic type.The second thing I've had happen is the fuse blown behind the battery inside the dash. Kills power to the coil and distributor. Worth a shot to check. Good Luck!
John
 
(quoted from post at 11:59:22 06/21/18) The load adjustment on the bottom of the carb. needs to be opened up more than you would think to pull a load good. It might be that simple ?

I checked the power load setting and it was out like 4 turns so I moved it to 2 turns and it improved a lot but still not quite right. Also the place who rebuilt the carb moved power adjusting screw to back side of carb instead of bottom. Could that make a difference?
 
Can you post a picture of your carb? There is nothing on that carb that can be moved. If it's different they sent you the wrong carb back. You should have a tag near the
top that say's TSX530.
 
(quoted from post at 07:52:49 06/22/18) Can you post a picture of your carb? There is nothing on that carb that can be moved. If it's different they sent you the wrong carb back. You should have a tag near the
top that say's TSX530.

18625.jpg
 
. Is the loss of power worse at low rpms or high rpms ?
Not the first time a cam was installed with a gear tooth one or two off spec.
Ignition advance ? How sloppy is the distributor bushing ?
 
I don't see a load screw. There should be a brass L screw on the bottom right. I see the nut's but not the load screw. How are you adjusting it?
 
Forgot to add. Can't tell from the pic but there is supposed to be a petcock in the very bottom near the center of the bowl.
 

Did your start over procedure and still can not tell much of a difference....it starts right away and sounds good at idle but soon as it is under a load like going up a hill it loses power and almost dies. Could it be a bad coil? replaced the condenser and points earlier. It seems to me it is in the carb but it was just rebuilt, maybe it is time to get a real mechanic in to look at it...
 

The carb was rebuilt and that is how it came back....since then I did add the load screw from another carb I had sitting around...did play with the settings but did not appear to make much of a difference.
 
Did TC/DC show when you went back to low idle? If so this proves the dist advance is functioning properly. This leaves fuel or air starvation. When you crank it up cold
spray some brake cleaner around the intake and carb gaskets. If it affects the engine there is a leak. Next leave the hose off the carb and try it. This proves the
breather. Next prove the carb fuel level and flow. Put a 1/8 hose barb with a couple feet or clear hose in place of the petcock on the bottom of the carb. Duct tape the
top of the hose to the side of the hood and fire it up. Fuel in the hose should be 1/4 in below the carb bowl gasket. It should stay there at full throttle. If these
tests pass yo are down to pulling the carb and finding the problem someone else missed. These are quite simple carbs and I'm sure you are more than capable of fixing it.
We can help you along if need be. I suspect whoever did your carb just put in a kit and didn't bother to clean out all the holes. A torch tip cleaner set will have all
the sizes you need. Just a few bucks at harbor freight or elsewhere. You would need to buy a couple screwdrivers and grind them to fit the nozzle and jets. The nozzle is
where you get the quick response and power. A plain screwdriver will rarely remove it so folks tend to either strip it out or leave it alone. You have to get a wide one
from napa or somewhere else and grind it to fit. Can't remember if it's a 5/16 or 3/8 I use but the thread size is 3/8 fine thread. Pretty sure it's the 5/16.
 
(quoted from post at 08:19:39 06/26/18) Did TC/DC show when you went back to low idle? If so this proves the dist advance is functioning properly. This leaves fuel or air starvation. When you crank it up cold
spray some brake cleaner around the intake and carb gaskets. If it affects the engine there is a leak. Next leave the hose off the carb and try it. This proves the
breather. Next prove the carb fuel level and flow. Put a 1/8 hose barb with a couple feet or clear hose in place of the petcock on the bottom of the carb. Duct tape the
top of the hose to the side of the hood and fire it up. Fuel in the hose should be 1/4 in below the carb bowl gasket. It should stay there at full throttle. If these
tests pass yo are down to pulling the carb and finding the problem someone else missed. These are quite simple carbs and I'm sure you are more than capable of fixing it.
We can help you along if need be. I suspect whoever did your carb just put in a kit and didn't bother to clean out all the holes. A torch tip cleaner set will have all
the sizes you need. Just a few bucks at harbor freight or elsewhere. You would need to buy a couple screwdrivers and grind them to fit the nozzle and jets. The nozzle is
where you get the quick response and power. A plain screwdriver will rarely remove it so folks tend to either strip it out or leave it alone. You have to get a wide one
from napa or somewhere else and grind it to fit. Can't remember if it's a 5/16 or 3/8 I use but the thread size is 3/8 fine thread. Pretty sure it's the 5/16.



Really showing my ignorance...having been checking timing and carb etc....i thought if i am getting spark and compression that cylinder must be firing, i am wrong took spark plug wire off while running and only no 1 cylinder is working, no 2 is sparking but no change in engine sound with or without wire. Am thinking this is not a good thing. Any new thought on the status of my tractor. Appreciate all the replies...thank you
 
(quoted from post at 17:03:18 06/30/18)
(quoted from post at 08:19:39 06/26/18) Did TC/DC show when you went back to low idle? If so this proves the dist advance is functioning properly. This leaves fuel or air starvation. When you crank it up cold
spray some brake cleaner around the intake and carb gaskets. If it affects the engine there is a leak. Next leave the hose off the carb and try it. This proves the
breather. Next prove the carb fuel level and flow. Put a 1/8 hose barb with a couple feet or clear hose in place of the petcock on the bottom of the carb. Duct tape the
top of the hose to the side of the hood and fire it up. Fuel in the hose should be 1/4 in below the carb bowl gasket. It should stay there at full throttle. If these
tests pass yo are down to pulling the carb and finding the problem someone else missed. These are quite simple carbs and I'm sure you are more than capable of fixing it.
We can help you along if need be. I suspect whoever did your carb just put in a kit and didn't bother to clean out all the holes. A torch tip cleaner set will have all
the sizes you need. Just a few bucks at harbor freight or elsewhere. You would need to buy a couple screwdrivers and grind them to fit the nozzle and jets. The nozzle is
where you get the quick response and power. A plain screwdriver will rarely remove it so folks tend to either strip it out or leave it alone. You have to get a wide one
from napa or somewhere else and grind it to fit. Can't remember if it's a 5/16 or 3/8 I use but the thread size is 3/8 fine thread. Pretty sure it's the 5/16.



Really showing my ignorance...having been checking timing and carb etc....i thought if i am getting spark and compression that cylinder must be firing, i am wrong took spark plug wire off while running and only no 1 cylinder is working, no 2 is sparking but no change in engine sound with or without wire. Am thinking this is not a good thing. Any new thought on the status of my tractor. Appreciate all the replies...thank you

Since there were no missing , sputtering or rough running sounds mentioned. This pointed to operation on one cylinder.
It is a common oops to mis-index the distributor , rotor ,cap and secondary wires on those tractors.
 
Had "B" and had same problem. I had gone to machine shop and they "did not" get the clearances correct. Used "too tight" clearance and when engine started to warm up it would not produce any power. Ran smooth but wouldn't function. I then tore down and changed block to a used block with standard pistons and problem solved. While this may not be your problem it would be worth examining. Did they use regular john deere pistons....really need to know more about the rebuilt. After my experience I have total quite using machine shops. Prefer to change out parts with used items installing "factory" rings only. More clearance is not a problem but too tight make the engine worthless. I would inquire with the person or firm as to exactly how they rebuilt. Best Chuck
 
(quoted from post at 05:58:45 07/01/18) Had "B" and had same problem. I had gone to machine shop and they "did not" get the clearances correct. Used "too tight" clearance and when engine started to warm up it would not produce any power. Ran smooth but wouldn't function. I then tore down and changed block to a used block with standard pistons and problem solved. While this may not be your problem it would be worth examining. Did they use regular john deere pistons....really need to know more about the rebuilt. After my experience I have total quite using machine shops. Prefer to change out parts with used items installing "factory" rings only. More clearance is not a problem but too tight make the engine worthless. I would inquire with the person or firm as to exactly how they rebuilt. Best Chuck

The tractor has sat for a while could that affect it...would putting some wd40 in cylinder maybe help? Will check with rebuild firm this coming week
 
You could try leaving the plug wire out abot a quarter inch and see if it starts firing then. I would go ahead and throw 2 new autolite 216's in there.
 
You know I think I would invest in a cylinder scope and see what is going on inside. You could do this prior to any work, tear down etc. You never said how much the machine shop did, the block or reassemble entire engine. You could go slow and see if all the valve train is operating properly. I seems like you are not knowledge about the mechanics but if there is a major problem again you may need to remedy some recovery from a machine shop etc. You could also run a compression test to see if the cylinder is building up the proper compression. Wish some of us could get our hands on the unit we could probably tell you where the problem lies....best Chuck

(quoted from post at 05:58:45 07/01/18) Had "B" and had same problem. I had gone to machine shop and they "did not" get the clearances correct. Used "too tight" clearance and when engine started to warm up it would not produce any power. Ran smooth but wouldn't function. I then tore down and changed block to a used block with standard pistons and problem solved. While this may not be your problem it would be worth examining. Did they use regular john deere pistons....really need to know more about the rebuilt. After my experience I have total quite using machine shops. Prefer to change out parts with used items installing "factory" rings only. More clearance is not a problem but too tight make the engine worthless. I would inquire with the person or firm as to exactly how they rebuilt. Best Chuck
 
Confirming spark by simply grounding the spark plug on the engine / tractor can be misleading. The added resistance of the engine's compression will affect the quality of the spark. A faulty spark plug can fire(produce spark) outside the tractor yet will not fire under compression.

That aside, are you certain you have the spark plug wires connected to the proper cylinder(firing order correct)? You mentioned adjusting the timing so it's possible that you have #2 on the distributor timed to the #1 cylinder which is why pulling the wire on #2 cylinder has no affect.

Food for thought.......


Really showing my ignorance...having been checking timing and carb etc....i thought if i am getting spark and compression that cylinder must be firing, i am wrong took spark plug wire off while running and only no 1 cylinder is working, no 2 is sparking but no change in engine sound with or without wire. Am thinking this is not a good thing. Any new thought on the status of my tractor. Appreciate all the replies...thank you
 

just went through a few more tests by swapping plugs from 1 to 2 also tried a new old wire on 2 cyl and still same result: pulling wire from plug does nothing to engine even tried a another spark plug which also made no difference. Earlier I did swap out the wires from the 2 cylinders and could not come close to timing it. I have used a timing light and have it timed pretty dead on. sounds really good at an idle. the no 2 cylinder has plenty of compression and also rechecked the valves and they are all really close. I am totally at a loss for what to even try next....
 
(quoted from post at 14:47:00 07/02/18)
just went through a few more tests by swapping plugs from 1 to 2 also tried a new old wire on 2 cyl and still same result: pulling wire from plug does nothing to engine even tried a another spark plug which also made no difference. Earlier I did swap out the wires from the 2 cylinders and could not come close to timing it. I have used a timing light and have it timed pretty dead on. sounds really good at an idle. the no 2 cylinder has plenty of compression and also rechecked the valves and they are all really close. I am totally at a loss for what to even try next....

We have been trying to tell you several times that the dead piston is not approaching TDC on the compression stroke when the plug fires .
 
okay here's one outside the box....about a year ago I worked on a 40 and it was really iratic...come to find out the switch and wire to the coil had failed making it misfire or not fire evenly. Try taking voltage directly to the coil and see what it does ...if you buy a resistor block you can be assured that you have 6 volts and make the wire direct from the battery...

(quoted from post at 13:06:31 07/02/18)
(quoted from post at 14:47:00 07/02/18)
just went through a few more tests by swapping plugs from 1 to 2 also tried a new old wire on 2 cyl and still same result: pulling wire from plug does nothing to engine even tried a another spark plug which also made no difference. Earlier I did swap out the wires from the 2 cylinders and could not come close to timing it. I have used a timing light and have it timed pretty dead on. sounds really good at an idle. the no 2 cylinder has plenty of compression and also rechecked the valves and they are all really close. I am totally at a loss for what to even try next....

We have been trying to tell you several times that the dead piston is not approaching TDC on the compression stroke when the plug fires .
 
Per buick and deere it appears your oil pump was not timed to the camshaft. He's exactly right as I recall the shaft has to be timed properly. It appears you have only got the #1 on timing and the #2 cylinder is not timed at all. You'll need to pull the oil pan and properly time the oil pump but before you do that check with the service manual and I believe you'll see what we're speaking about. Sounds like someone assembled items without proper procedure....

(quoted from post at 17:07:44 07/02/18) okay here's one outside the box....about a year ago I worked on a 40 and it was really iratic...come to find out the switch and wire to the coil had failed making it misfire or not fire evenly. Try taking voltage directly to the coil and see what it does ...if you buy a resistor block you can be assured that you have 6 volts and make the wire direct from the battery...

(quoted from post at 13:06:31 07/02/18)
(quoted from post at 14:47:00 07/02/18)
just went through a few more tests by swapping plugs from 1 to 2 also tried a new old wire on 2 cyl and still same result: pulling wire from plug does nothing to engine even tried a another spark plug which also made no difference. Earlier I did swap out the wires from the 2 cylinders and could not come close to timing it. I have used a timing light and have it timed pretty dead on. sounds really good at an idle. the no 2 cylinder has plenty of compression and also rechecked the valves and they are all really close. I am totally at a loss for what to even try next....

We have been trying to tell you several times that the dead piston is not approaching TDC on the compression stroke when the plug fires .
/quote]
 
Well, you've at least ruled out a faulty spark plug & wire.

You still need to confirm if #2 cylinder is getting spark at the appropriate time.

This quick check will confirm that:

With distributor cap installed, put marks(felt/paint pen) on the distributor body indicating the position of #1 & #2 contacts. Remove distributor cap but leave rotor in place.

Remove spark plugs. Put finger/thumb over #1 plug hole pushing hard enough to make a seal. Roll engine over in direction of rotation(CW when viewed from the front) slowly until compression is observed. You should(will) notice the rotor approaching the #1 mark on the distributor housing.

Put finger/thumb over #2 plug & continue to roll engine over in the direction of rotation until compression is observed. If the rotor is approaching the #2 mark on the distributor housing, the distributor indexing is good. If it's no where near(as in way past) you've found your problem.

Worth a try. Probably take less that then minutes to check......



(quoted from post at 11:47:00 07/02/18)
just went through a few more tests by swapping plugs from 1 to 2 also tried a new old wire on 2 cyl and still same result: pulling wire from plug does nothing to engine even tried a another spark plug which also made no difference. Earlier I did swap out the wires from the 2 cylinders and could not come close to timing it. I have used a timing light and have it timed pretty dead on. sounds really good at an idle. the no 2 cylinder has plenty of compression and also rechecked the valves and they are all really close. I am totally at a loss for what to even try next....
 
Agree. While you are at it stand right
beside the dist and take a pic and post it.
I can tell by that if the pump is timed
correctly.
 
For starters you have the plug wires reversed. facing the distributor the rear cylinder wire is to the left of the distributor #1 plug is to the right. Your distributor is rotated too much counterclockwise...however this doesn't tell me where the distributor rotor is located or where it was timed with the crankshaft. I think the distributor turns only one round per two rounds of the engine, however I may be incorrect there. For a note a few clicks of the mouse on some sights can show the location of the distributor wires. I note your wires are incorrect and I would start with a new set of the exact wires for the tractor. These look like just some automotive wires being used. Do a little more digging and I think you will resolve your issues. A tech manual may be a start.

(quoted from post at 08:38:56 07/05/18)
19280.jpg
19281.jpg
 
Front is no#1. You have no#2 wire going to
it. Small Dist wire post needs to go
towards the front which should then point
the rotor towards the #1 dist post where it
should be. Then you can reset the timing
with a light You do need to go to Napa and
get a set of solid copper core wires. Have
to buy them for a 4 cylinder and cut to
fit. The ends will crimp on.

If you want to double check the pump timing
remove both plugs and turn the engine until
you feel air pushing out the front spark
plug hole. Look in the timing window and
when you see DC centered stop. You can now
pull the Dist. The slot in the drive at the
bottom should be straight ahead. Wider part
towards the outside.
 
(quoted from post at 05:42:12 07/06/18) Front is no#1. You have no#2 wire going to
it. Small Dist wire post needs to go
towards the front which should then point
the rotor towards the #1 dist post where it
should be. Then you can reset the timing
with a light You do need to go to Napa and
get a set of solid copper core wires. Have
to buy them for a 4 cylinder and cut to
fit. The ends will crimp on.

If you want to double check the pump timing
remove both plugs and turn the engine until
you feel air pushing out the front spark
plug hole. Look in the timing window and
when you see DC centered stop. You can now
pull the Dist. The slot in the drive at the
bottom should be straight ahead. Wider part
towards the outside.
mvphoto19338.jpg



Loaded pic of distributer hole when lined up with Spark not any where near pointing to no 1 cylinder
 
Good photos but the actual location of the pump grove would not keep the tractor from operating properly. From my experience the distributor can turn 360 degrees and it could be properly timed. Now having said that the location of the distributor would possibly not be factory and wires may not be close to block. Did you get the proper wires and follow the advise of M-M and myself?
 
(quoted from post at 14:41:51 07/06/18) Good photos but the actual location of the pump grove would not keep the tractor from operating properly. From my experience the distributor can turn 360 degrees and it could be properly timed. Now having said that the location of the distributor would possibly not be factory and wires may not be close to block. Did you get the proper wires and follow the advise of M-M and myself?

Ordered new wires. ...really appreciate all the input...thank you
 
Try again. I don't think you are on #1
compression stroke. If it is the small Dist
post would need to be pointing towards the
block for the rotor to point to the #1
post. That Dist will only go in one way.
Turn the engine again and wait for the air
to push your thumb off. Keep turning untill
you see DC and stop.
 
What is happening with this. As a long time owner of a 40 and a 420, I am curious to see where this goes.

CPeter
 
I'm also baffled as to how something simple is made so complicated.

(quoted from post at 04:20:18 07/09/18) What is happening with this. As a long time owner of a 40 and a 420, I am curious to see where this goes.

CPeter
 
A presumption on my part but with the advantage of many years of experince I can see how it would seem that way.

I can remember back when I started in the trade, working at a place that serviced & overhauled engines right from 1 cyl up to V16 in size. I overhauled our 40 at the farm during my time off and in process managed to mix up #1 & #2 plug wires. Not sure how it happened as I was dealing with the firing orders of 8, 12, & 16 cylinder S.I. engines on a regular basis.

Bottom line is anyone can make the mistake regardless of who they are. At the time a person forgets about the basics & looks at all other angles. A case of missing the forest for the trees.
 
Glen: You're right on the point...I've overlooked the most simple things....those 2 cylinders are a little tricky to the new comer....number 1 cylinder was always referred as the lead cylinder...with the cylinders firing 90 degrees apart then having a 11/2 rev to come back to number 1. If he can get the lead cylinder timed he should have it...provided he doesn't have some current or other wiring problems...I see someone has wired up an alternator so I suspect a lot of other things have been modified.

(quoted from post at 08:57:36 07/10/18) A presumption on my part but with the advantage of many years of experince I can see how it would seem that way.

I can remember back when I started in the trade, working at a place that serviced & overhauled engines right from 1 cyl up to V16 in size. I overhauled our 40 at the farm during my time off and in process managed to mix up #1 & #2 plug wires. Not sure how it happened as I was dealing with the firing orders of 8, 12, & 16 cylinder S.I. engines on a regular basis.

Bottom line is anyone can make the mistake regardless of who they are. At the time a person forgets about the basics & looks at all other angles. A case of missing the forest for the trees.
 

hey just to update my progress I did finally get the tractor to run with both cylinders....it was in the timing of the oil pump...took me several times but it is definitively running on both and actually sounds good....appreciate all the comments and help...Thank you
 
(quoted from post at 13:55:51 07/31/18)
hey just to update my progress I did finally get the tractor to run with both cylinders....it was in the timing of the oil pump...took me several times but it is definitively running on both and actually sounds good....appreciate all the comments and help...Thank you

That you for the update . Those “they lived happily ever after “ make it all worthwhile here .
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top