AC 7020 Running Hot Exhaust

I bought a 7020 this fall, and have gradually been trying to get the bugs worked out of it.  I've gone through the things I knew needed work when I bought it. Now, I am finding things that I didn't expect.

I have noticed that it blows a lot of black smoke, even under moderate load. Last night I hooked it up to a small chisel plow and after about 10 minutes, I noticed that had an orange glow about 8-10 inches out the top of the muffler. When I stopped and got out, I noticed that the exhaust manifold and turbo had an orange glow to them. I left it on high idle and got an IR thermometer from the garage. After running it under load for a few minutes, I would get temp readings around 950 degrees most places, with a few of the hottest spots being in excess of the 999 of the thermometer's max readout.

FWIW, I could hold rated engine speed in 4th gear HI, but had to run in 3rd gear LO to keep the temps to what I noted above. This resulted in no flame out the top of the muffler. I am sure I ran it at a higher temp for the 10 minutes or so before I stopped to check things out. Temperature gauge never moved past normal operating temperature. I did let it idle at least 10 minutes after a 5 minute drive back to the yard. This morning I noticed that the exhaust port to the #5 & 6 cylinders has cracked off from the rest of the manifold. So, something is obviously in need of remedy. Is what should I look for, or did someone just turn up the fuel too much? It did previously have a leaky gasket for the front exhaust port. I found the bolts loose, and tightened them, but that didn't totally stop it. That was on my plan of things to replace during winter down time, as it didn't seem to be too big of a deal.

Should it smoke like a super stock puller though? Maybe not quite that much, but it's a lot of smoke, even pulling a 13' disk running 4" deep in corn stalks.

Will retarded timing also make for hard cold starting? It's gotta be plugged in below 45 degrees or it will NOT start. Doesn't like to start  below 20 degrees, even if it's been plugged in all day. Maybe I just need a bigger block heater.

It slobbers a bit of oil out of the breather, but the but I've run stuff for years with worse blowby for sure.

Could a leaking exhaust gasket let out enough pressure to reduce boost pressure, and thereby lead to an overfuel situation? I am thinking I should put on a new manifold and install a pyromometer and boost gauge to see what is going on.

Some facts about a 7020 tractor. #1. They are kind of known for breaking exhaust manifolds (over time that is). I blame it on two things.....the big heavy muffler and probably higher exhaust temps due to the 123 PTO HP.   #2. They are quite famous for having manifold bolts working loose. Again, I blame that on the same two things, You'd be wise to install new AGCO manifold bolts when installing a new manifold. They are a SPECIAL bolt, so don't buy anything but the AGCO bolts. I advise checking bolt torque every engine oil change to keep them tight.   #3. 7020's normally do smoke like a Mack truck when throttling up and when the engine hits about 1800 RPM, the turbo spools up and the heavy smoke goes away. This is NORMAL....get over it.   #4. Maximum exhaust temps are around 1250 to 1300 degrees as per the Service Manual. If the injection pump has been "turned-up", just shift down a gear and less HP will be produced by the engine. A 30 psi gauge tapped into the intake manifold will indicate actual turbo boost. A 7020 would be around 20 psi full load on a 70 degree day. More boost will show in cold weather.

Thanks guys for all the information. A couple more questions.

How hard is it to check the timing, and undo "turning up" the pump.

It smokes black at all rpm. I don't notice it lessening until the load lightens. There's visible, but not really thick smoke at full speed cruising down the road with no load.

One other thing, the tach reads 2700 rpm at WOT, is the tach that inaccurate, or has the governor been messed with.

It seems to have plenty of power, but factory spec is 75% more than my previous largest tractor. I would probably feel like it not sluggish at 100 hp.

It's definitely pretty sluggish at low rpm, which I just figured is the nature of a motor with a turbo.