John Deere MT

[Gene Davis]

We continue to have problems with this tractor wanting to flood out. It appears to be fouling one of the plugs. I changed from Champions to Autolites,but this didn't work.

I cannot find any air leaks on the carb or intake.

Tried to located with Cab cleaner to no avail.

I am thinking of advancing the timing slightly.

Anybody got any ideas?

 

[greygoat]

Flooding out is a carb problem, check the float
level, or check for bad float, or replace leak-
ing needle valve.

 

[Gene Davis]

We have overhauled carb.

How do you tell is float is bad?

 

[twomen]

Ah, will it float?

 

[rustyfarmall]

Submerge the float in water. You will have to hold in down. Watch for air bubbles coming out of the float. If you see bubbles, the float leaks, and should be replaced.

 

[Wayne from MN]

If it is a hollow metal float, shake it close to your "good" ear & listen for liquid sloshing around inside.

 

[Glen D Anderson]

Compression good & even??

Coolant leaking into cylinder that is fouling plug?? Put pressure on rad. to see if coolant ends up in cylinder(using radiator pressure tester)

Plugs - Autolite 216??

Timing set to OEM specs.??

If all those items check out then there could be issues with carb. and/or its adjustment...............do you get black smoke from exhaust at idle and/or under load?? If so issues with idle or load circuit may be present...........

 

[Gene Davis]

Glen,

Thanks for all the info.

We are not getting coolant in the oil. O/P is great.

Black smoke(occassionally)under load.

Yes A/L 216. We had this tractor at a show last week.

The plug in #2 was trying to flow. I dind't have plug wrench or spares. I pulled plug wire and tried to jump fire to make it burn hotter. This worked sporatically.

I am going to change plugs and advanced timing slightly. (By ear)

The weird thing is it runs pretty good not under a load. When you load it, it tries to die, mis fires on one cylinder. You have to pull the choke all the way out for it to run.

The low speed screw is broken off. When we were trying to rebuild, we tried to turn and broke off.

It didn't move so our theory is it is probably right.

If this doesn't work,my next step is take the carb off, soak the stew out of it, rebuild and put new floats in it.

I have sprayed carb cleaner and tried to see about and air leak. I couldn't find anything.

Any suggestions, would be apprecaited.

 

[Glen D Anderson]

You may not necessarily be getting any noticeable amount of coolant in oil but rather enough in the combustion chamber to help foul the plug............I encountered this with our 40U, it had a cracked cylinder head which made it necessary for regular plug changes..................

As you mentioned, confirming 100% if the plugs are good can save you alot of headaches..........

From what you say about using the choke to help the engine run during loaded operation it sure sounds like a problem in the load circuit(lean)......your test of the intake system integrity should have ruled out vacumm leaks as well................

A complete disassembly and proper cleaning of the carburetor will yeild positive results........

You never mentioned if compression was good though??

 

[buickanddeere]

Is the remaining adjustment screw dialed all the way in or out?

 

[Gene Davis]

Haven't checked compression.

Tractor start easily. This tractor set up for 20+ years. O/P is good.

We are going to drill out the lean misture screw and replace. I am going to order another rebuild kit and new floats.

Sure appreciate all your help. Me and the other Grandpa restored this tractor for our 2 1/2 year Grandson. He is a tractor nut. We spent a lot of time, effort and money restoring this. It looks great and I weant to resolve this final issue no matter what it takes. I am just trying to figure the problem out.

Thanks.

 

[Gene Davis]

If you are talking about the l shaped brass screw on the bottom of the carb, its' neither.

It was my uinderstaingthat this was the load adjustment screw that needed to be adjusted with the throttle wide open.

We have fooled with it and it's probably about 1 1 1/2turns open.

Any suggestions?

 

[John Heine]

Compression good?Air test cylinders for leakeage

 

[Gene Davis]

Will do.

Tractor does not use any oil.

 

[Glen D Anderson]

If the compression checks out, a thorough rebuild of the carb will likely have you off to the races.............

I would suggest a complete diassembly of the carburetor followed by a soaking of the parts in a proper carburetor cleaner/bath for as long as possible, then clean and inspect ALL carburetor passages for restrictions using compressed air and a rubber tipped air nozzle..........wire, torch tip cleaners, drill bits, sand blasting, etc, can be used to remove debris from the passages providing common sense is used.............the quality of ANY carburetor overhaul is directly proportional to the cleanliness of the passages............

These are great little tractors, both to work on and to operate............

 

[Gene Davis]

Glenn,

I'm ahead of you this one. I ordered the rebuild kit as well as new floats today.

We have some heavy duty carb cleaner that we will soak in.

I plan to start the soaking process this weekend.

My thought was that if the carb is too rich, it may be causing the fouling of the plugs with carbon.

I'm going back to the Cahmpion HC 10's.

Thanks for all you help and advise.

 

[KF]

Just to check out your ignition system, put a timing light on each of the spark plug wires and see if you get constant firing without out any misses. It will show up in the flashing rate of the timing light. Could have something weak in the ignition system that is causing a miss under load.

 

[Gene Davis]

Will do.

Thanks