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Pooh Bear 38
09-25-2010, 12:30 PM
Hello All, Two months ago, I purchased a 1938 B long frame John Deere, that went through a two year restoration. On the outside she is a ten all the way. Mechanics completed were new rings, pistons, turned the crank, ground the valves, I was told the head looked very good. Rebuilt carb, magnito, new radiator, new fuel lines, fuel bowl and all new rubber and John Deere paint and decals. 10-40 oil was placed in the crankcase by the seller in June of this year. I was informed that the tractor ran great, no smoke and just needed a coat of wax on the hood tin for the shows. I have been running the tractor once a week for about an hour, 8 hours total time so far. Tractor was smoking blue smoke out the stack in the beginning, not real bad and then the smoke got less and the tractor seemed to be running better until she was hard starting ten days ago. It is a hand start. I got her going and she ran good and then when I went to start her a week later she would not start. Pulled the right side plug as you sit on the seat and it was fouled with oil. drained the crankcase and put 40 weight oil in with a new filter per the manual 40 weight oil for 65 to 90 degree heat. Put in a new plug and she started. I drove her for about an hour, she was not running as smooth, however she did not cough or sputter either. After turning her off, I pulled that same right plug and it had a lot of oil on it. Put my pinky finger in the plug hole and fished out a very small piece of white metal and there was gritty oil substance on my finger. This problem has been driving me crazy, because from the outside the tractor is a showpiece. I was told that maybe the right side rings have not seated yet and that the tractor needs to be worked to seat the rings properly. Others have told me that there is a problem probably with the rings on that right piston or in the head. There is good spark to both plugs from the magnito. She idles a little high and my throttle bolt is adjusted as low as she can go and the idle is still a little too high. I would like to find the problem, so that I can get her to run better and not smoke and idle better. The 10-40 oil I removed came out very black and it was only in the crankcase for two months. The previous owner drove the tractor once a week in low one for a few months. Any suggestions and opinions would greatly be appreciated. I am almost ready to call a local john deere tractor repair shop, however not many folks are familiar with an old 38 and I am afraid my bill might cause me to have to get a second job. Thanks to all for any suggestions and opinions.

Red Beard
09-25-2010, 07:36 PM
Would like to know what the little piece of white metal was. How big and was it magnetic? I wonder how round and square the cyls are. It's hard to tell unless you've been inside. When I do an engine, it doesn't idle any longer than necessary and after a very few mins, it starts making power. I watch mainly the temp but make them work pretty hard for 30 to 50 hours till the rings are seated, otherwise they might glaze. You might have a wrist pin problem. Anything else I can say to help your paranoia?

Pooh Bear 38
09-25-2010, 08:07 PM
Hello Red Beard,
Thanks fior the reply. The piece of metal was approximately 1/16th of an inch long and I believe had some green paint on it. Was it magnetic, I do not know, but it looked like a soft piece of white metal. As I said before the tractor was driven once a week for awhile buy the guy who rebuilt it only in first gear at 1 or 2 miles an hour. I have been driving it on the road in H2. If after I take it out another three or four times and it is still showing oil on the same plug and still smoking somewhat, what would you suggest?? I am not that good of a mechanic to take the head off, but I am sure I can find someone. I did not mention that the first time I drove it, I had it in Low 2 and after about 20 minutes the temperature gauge went up to about 210 degrees and I had to bring it home. Since then she went from about 195-200 degrees down to 190 the last few times I took it out. Also when I am in H2, I can hear a chain noise coming from in front of the seat area, it is almost like a chain slapping. The quicker I go the more it will sound, the slower the less noise it will make. Its too bad because as I said earlier, the outside of the tractor is in mint condition for a 38. I don't want to give up hope, however I don't want to spend a fortune on fixing it either. I thought I was buying a turn key restored 38 that did not need anything. Any suggestions to help this 60 year old green horn would be much appreciated. Could it be that the rings on the piston fouling the plug are not broke in??? Will this condition do any harm to the motor?? Thanks again.
Pooh Bear 38

Pooh Bear 38
09-26-2010, 08:13 PM
Would like to know what the little piece of white metal was. How big and was it magnetic? I wonder how round and square the cyls are. It's hard to tell unless you've been inside. When I do an engine, it doesn't idle any longer than necessary and after a very few mins, it starts making power. I watch mainly the temp but make them work pretty hard for 30 to 50 hours till the rings are seated, otherwise they might glaze. You might have a wrist pin problem. Anything else I can say to help your paranoia?
The piece of metal was approximately 1/16th of an inch with some green paint on it, I don't know if it was magnetic or not, but I just learned something tonight that might be of interest. I was told that the two cyclinder John Deeres are very good on gas, well I had about six hours of operating time on mine and she ran out of gas. I started with about six gallons of gas, that sounds like a lot too me. I put in five more gallons and ran another 2 1/2 hours and I checked the gas tonight and she is almost empty again! I know I am a green horn to tractors, but could my problem be not oil but way too much gas that is casuing the tractor to smoke and foul the right side plug? I smelled the plug and it did not smell like gas and it felt like oil too me, but why is she burning so much gas?? Also when I am running in High two I can hear what sounds like a chain slapping possibly in the tranny. I was told that the old John Deeres will sometimes make a chain noise but it should not be alarmingly loud. Could the left side have seated the rings and the right side not? Any responce to assist with my problem would be very much appreciated. Thanks

Red Beard
09-27-2010, 12:25 AM
Exactly what model is your toy according to the ID plate. If the letter designation is BNH or BWH, then it probably has a chain in the differential which would probably slap, more so at higher road speeds. The carb has two mixture screws. The idle screw is brass plated and closest to the outside while the high speed or load screw is cad plated and is on the back side. Both are on the top of the carb. When tightening these, be gentle so you don't make a dented ring on the needle. The idle screw should be about 1 to 1 1/4 turns open while the load should be 3/4 to1 turn open. These are approximate, your engine is running, so try to forget these settings and simply adjust them for the smoothest operation at an idle and at high rpm. If these adjustments are way off, you might have to go back and forth a couple times to get them right. You might have to clean or reshape the needles with a good flat stone if they are pitted or have bad rings (dents) in them. ( you could also use a small lath :) )If the compression is too bad in the one cyl, or the mixture too rich, some of the fuel could collect in the crankcase which you can either tell by smell or a raise in the oil level at which point you either have to change it or get it hot enough to evaporate the gas! Have fun!

Pooh Bear 38
09-28-2010, 08:46 AM
Hi Red Beard,
The tractor is a B serial 53627. The load screw is out 1/2 turn and the idle screw is out one full turn. Everytime I park the tractor I can find what looks to be a little oil or fluid underneath both spark plugs, I was told that is a classic sign of the motor burning too rich. I was told to unscrew the load screw and take it out gently to inspect it and replace with a light coat of oil on the threads and readjust the carburator. If that does not work then the carburator will have to be inspected. I was told that most likely my problem is with the carburator and not any oil coming from the motor, I hope so. I found a good John Deere mechanic, who is going to come out to my house if my friend and I cannot find the prioblem. Thank you for your imput.

MBDiagMan
09-28-2010, 11:23 AM
Burning rich will result in a black fluffy deposit on the plug. Burning oil will result in a wet, OILLY substance on the plug. Very easy to distinguish between the two.

Is the smoke blue or black?

Pooh Bear 38
09-29-2010, 11:17 AM
The smoke appears to be blue in color and I agree the substance on the plug in my opinion is oil.

MBDiagMan
09-30-2010, 10:20 AM
Okay, it is for sure oil and I'm sure you've already concluded this.

It's time to do a compresson check or better yet a Leak Down Test. If all you have to use is a compression gauge, remove plugs, do the compression check and write down numbers. THEN put a table spoon full of oil in a cylinder and recheck compression and write it down, then a table spoon in the next cylinder and so forth. If the compression comes up with the oil in the cylinder the problem is piston/ring/cylinder related, if not it is a really bad intake valve guide.

If you are equipped to do a Leak Down Test, connect equipment and more important than the numbers is listening for where the air is escaping from the offending cylinder. If you hear it in the crankcase or through the oil filler, it's piston/ring/cylinder related. If you hear it through the carburetor it's an intake valve and if through the exhaust the problem is an exhaust valve.

Hope this helps,

Pooh Bear 38
10-01-2010, 08:40 AM
My friend and I started the tractor yesterday, got her up to 190 degrees and readjusted the idle mixture and load mixture. We ran the tractor for about an hour and she ran very good as always except for some smoke out the stack. We then pulled the right plug and it had some oil on it as usual. I was told by a John Deere mechanic, to put in two hot plugs and run it for another hour and then pull the plugs to see what they look like. Three out of four knowledgable John Deere people tell me that the rings on the piston for that plug may not be seated as of yet and that if I had an opportunity to work it in the field the problem may clear up. I don't believe there is more then 15 running hours on this tractor since it had new rings and pistons, plus she is 72 years old. My friend feels that she runs real good and to leave it alone and just put a new plug in or clean it every four or five times I take it out. I am being mentered by a John Deere mechanic here in Connecticut and I will give him your suggestions. Thank you for your assistance and suggestions any other thoughts would also be appreciated. This tractor has never stalled, sputtered or coughed since I have had it on the road about 8 or 9 different times now. In your opinion without the compression test or leak down test do you think it could be that the rings are not seated on the right side bank?? This tractor is a hand start and it may be difficult to do a compression test?? Would the oil on the right side plug cause any further harm in the furture, say the next few years. This tractor is a show tractor that I like to drive and would like to show it next spring. Thanks again.

MBDiagMan
10-04-2010, 07:51 AM
Do you know what kind of rings were used? Were they cast iron or otherwise? If cast iron, they should have already seated with no trouble, but given that it is not loaded, rather just driven for parades and such, this could indeed be the issue.

Being that it is a show tractor, if you decide to work it in the field, make sure you do it under the right weather and soil conditions so you don't spoil all the nice paintwork and such.

As far as it doing damage, the only damage that the oilly plug is causing is to the plug itself. For your purposes, I would just get a few extra plugs and a small spark plug bead blaster. Keep an extra, clean plug and the tools to change it at hand and enjoy your parades.

My $0.02,