MF 135 loss of power

Hello there, I was cutting the field yesterday and got stuck with the bush hog in a low spot and the tractor stalled due to the effort. It started fine and I got out but noticed not long after that it was struggling to cut areas easily done before. It also seems like this was getting worst quickly so I headed back to the shop to see what was wrong. Now it still starts fine but instead of the small puff of black smoke it use to do when quickly increasing the rpm, it now produces a whitish smoke instead and it sounds like it misses one cylinder all together. I replaced the head gasket three years ago after I pushed it too hard on the snow blower and it has been very reliable since. I was ready to lift the head again thinking it is probably the same thing because I stalled it. I am looking for advice on what it could be before I pull the head again. Are those tractors very sensitive when it comes to overloading the engine? I have put a small video showing the exhaust fumes it now produces : https://youtu.be/VPwWQITSUqk

Looking forward to your support.
Youtube video, smoky mf 135

Not sure on the exhaust smoke, but does not sound right. I always thought they were a tough tractor. I have one with the 3 cylinder Perkins gas. and do run it hard and no problems with engine. The weakness on mine is the power steering.

Might pull the rocker cover, look the valve train over, broke spring, bent pushrod, etc.

Can you run a compression test? Or disconnect the kill solenoid/hold the kill lever, crank it through and listen to the starter, see if you hear a low cylinder cranking through.

It could be a head gasket, bent valve, or?. Any excess blow-by? Running hot, blowing coolant?

I have the same motor in my MF 203. I was in a area where it was pulling harder going up a hill. The head gasket blew out between two cylinders. It would hardly run on the only good cylinder, to get it back on my trailer. Your tractor may not have that problem. I would crack the injector lines to see if the problem is on one cylinder, or two. If two, it may be a gasket. If one it may be related to that cylinder only. Stan

(quoted from post at 12:18:57 07/19/16) Might pull the rocker cover, look the valve train over, broke spring, bent pushrod, etc.

Can you run a compression test? Or disconnect the kill solenoid/hold the kill lever, crank it through and listen to the starter, see if you hear a low cylinder cranking through.

It could be a head gasket, bent valve, or?. Any excess blow-by? Running hot, blowing coolant?

Click to expand...

I am not equipped to take the compression, what would the sound of a low cylinder be like?

It is very similar to what happened three years ago, the gasket was blown between cylinder 1 and 2, couldn't make it back to the shed on its power then. I will crack the injector line to locate the defective cylinder. Is it possible to reuse the head gasket if that isn't the problem? I know they aren't so expensive but I would have to order online as no suppliers are nearby.

Thanks

(quoted from post at 12:45:45 07/19/16) I have the same motor in my MF 203. I was in a area where it was pulling harder going up a hill. The head gasket blew out between two cylinders. It would hardly run on the only good cylinder, to get it back on my trailer. Your tractor may not have that problem. I would crack the injector lines to see if the problem is on one cylinder, or two. If two, it may be a gasket. If one it may be related to that cylinder only. Stan

Click to expand...

Thank you for the info, my tractor with the 3 cylinder Perkins blew the gasket between cyl. 1 and 2 a while ago. It was fitted with a copper gasket and I replaced it with the same. When you replaced your head gasket, was the blown one copper or the fabric/asbestos type? Just wondering if I should replace it with another copper one or go with the other type. I'll do as you suggest and loosen the injector lines to locate the one not firing.
thank you.

I believe the gasket that I used that blew out between cylinders, was a fiber type. Years ago I heard people would soak the copper gaskets over night in water to make them swell up, and reuse them. I don't think I would chance using the gasket over. Stan

(quoted from post at 12:18:57 07/19/16) Might pull the rocker cover, look the valve train over, broke spring, bent pushrod, etc.

Can you run a compression test? Or disconnect the kill solenoid/hold the kill lever, crank it through and listen to the starter, see if you hear a low cylinder cranking through.

It could be a head gasket, bent valve, or?. Any excess blow-by? Running hot, blowing coolant?

Click to expand...

How can I measure the blow by, what is acceptable? Thermostat maintain the temp between 180-190, oil pressure is good 50 psi cold down to 45 range when hot. I just cracked all the injectors one by one and seems like all pistons are firing on iddle. I found that the air filter hose was cracked and collapsing somewhat because of the succion but that has nothing to do with it as I remove the hose and same problem. I created a leak tightening the injectors and one return is leaking a bit. The #2 injector is also wet at the junction between the two halves. I plan on checking the spray pattern by pivoting the injectors out and cranking it, would that be a good way of testing that? The coolant seems fine, the smoke definitely smells like unburned fuel.
Many thanks for your help.

"the sound of a low cylinder"

You listen to the starter labor, develop a pattern, listen for one compression stroke to spin through easier. It takes an ear for it, has to be a substantial compression loss.

On a gas engine, a leak-down tester would measure how well a cylinder hold compression (blow by) and help you locate where it is leaking: rings, intake valve, exhaust valve or into the cooling system. I don't know it they are made for diesels.

UPDATE: I just removed the valve cover and the adjustment for the #2 exhaust valve is off with a gap of 1/2 inch... The adjustment nut came loose and the adjustable part below the rocker screwed itself in with the vibration.

I think I am out of the woods ;-).

Thank you very much for all your suggestions, this forum is wonderful.

Good news. Stan